11.. primitive data types and variables - eemb · pdf file10/3/2011 1 primitive data types and...

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Primitive Data Primitive Data Types and VariablesTypes and Variables

Creating and Running Your First C# ProgramCreating and Running Your First C# Program

Table of ContentsTable of Contents

1.1. Primitive Data TypesPrimitive Data Types

�� Integer Integer

�� FloatingFloating--Point / Decimal FloatingPoint / Decimal Floating--PointPoint

�� BooleanBoolean

�� CharacterCharacter

�� StringString

�� ObjectObject

2.2. Declaring and Using VariablesDeclaring and Using Variables

�� IdentifiersIdentifiers

�� Declaring Variables and Assigning ValuesDeclaring Variables and Assigning Values

�� LiteralsLiterals

3.3. NullableNullable typestypes

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Primitive Data TypesPrimitive Data Types

How Computing Works?How Computing Works?

�� Computers are machines that process dataComputers are machines that process data

�� Data is stored in the computer memory in Data is stored in the computer memory in

variablesvariables

�� Variables have Variables have namename, , data type data type and and valuevalue

�� Example of variable definition and assignment Example of variable definition and assignment

in C#in C#

int count = 5;int count = 5;Data typeData type

Variable nameVariable name

Variable valueVariable value4

What Is a Data Type?What Is a Data Type?

�� A A data typedata type::

�� Is a domain of values of similar characteristicsIs a domain of values of similar characteristics

�� Defines the type of information stored in the Defines the type of information stored in the

computer memory (in a variable)computer memory (in a variable)

�� Examples:Examples:

�� Positive integers: Positive integers: 11, , 22, , 33, , ……

�� Alphabetical characters: Alphabetical characters: aa, , bb, , cc, , ……

�� Days of week: Days of week: MondayMonday, , TuesdayTuesday, , ……

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Data Type CharacteristicsData Type Characteristics

�� A data type has:A data type has:

�� Name (C# Name (C# keyword or .NET type)keyword or .NET type)

�� Size (how much memory is used)Size (how much memory is used)

�� Default Default valuevalue

�� Example:Example:

�� Integer numbers in C#Integer numbers in C#

�� Name: Name: intint

�� Size: 32 bits (4 bytes)Size: 32 bits (4 bytes)

�� Default value: 0Default value: 0

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Integer TypesInteger Types

What are Integer Types?What are Integer Types?

�� Integer types:Integer types:

�� Represent whole numbersRepresent whole numbers

�� May be signed or unsignedMay be signed or unsigned

�� Have range of values, depending on the Have range of values, depending on the size of size of

memory usedmemory used

�� The default value of integer types is:The default value of integer types is:

�� 00 –– for integer types, exceptfor integer types, except

�� 0L0L –– for the for the longlong typetype

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Integer TypesInteger Types

�� Integer types are:Integer types are:

�� sbytesbyte ((--128 to 127): signed 8128 to 127): signed 8--bitbit

�� bytebyte (0 to 255): unsigned 8(0 to 255): unsigned 8--bitbit

�� shortshort ((--32,768 to 32,767): signed 1632,768 to 32,767): signed 16--bitbit

�� ushortushort (0 to 65,535): unsigned (0 to 65,535): unsigned 1616--bitbit

�� intint ((--2,147,483,648 to 2,147,483,647): signed 2,147,483,648 to 2,147,483,647): signed

3232--bitbit

�� uintuint (0 to 4,294,967,295): unsigned 32(0 to 4,294,967,295): unsigned 32--bitbit

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Integer Types (2)Integer Types (2)

�� More integer types:More integer types:

�� longlong ((--9,223,372,036,854,775,808 to 9,223,372,036,854,775,808 to

9,223,372,036,854,775,807): signed 649,223,372,036,854,775,807): signed 64--bitbit

�� ulongulong (0 to 18,446,744,073,709,551,615): (0 to 18,446,744,073,709,551,615):

unsigned 64unsigned 64--bitbit

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Measuring Time Measuring Time –– ExampleExample

�� Depending on the unit of measure we may use Depending on the unit of measure we may use different data types:different data types:

byte centuries = 20; // Usually a small numberbyte centuries = 20; // Usually a small number

ushort years = 2000;ushort years = 2000;

uint days = 730480;uint days = 730480;

ulong hours = 17531520; // May be a very big numberulong hours = 17531520; // May be a very big number

Console.WriteLine("{0} centuries is {1} years, or {2} Console.WriteLine("{0} centuries is {1} years, or {2}

days, or {3} hours.", centuries, years, days, hours);days, or {3} hours.", centuries, years, days, hours);

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Integer TypesInteger TypesExamples 02Examples 02--01;0201;02--0202

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FloatingFloating--Point and Decimal Point and Decimal FloatingFloating--Point TypesPoint Types

What are FloatingWhat are Floating--Point Types?Point Types?

�� FloatingFloating--point types:point types:

�� Represent real numbersRepresent real numbers

�� May be signed or unsignedMay be signed or unsigned

�� Have range of values and different precision Have range of values and different precision

depending on the used memorydepending on the used memory

�� Can behave abnormally in the calculationsCan behave abnormally in the calculations

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FloatingFloating--Point TypesPoint Types

�� FloatingFloating--point types are:point types are:

�� float float ((±±1.51.5 ×× 1010−45−45 to to ±±3.43.4 ×× 10103838): 32): 32--bits, bits,

precision of 7 digitsprecision of 7 digits

�� double double ((±±5.05.0 ×× 1010−324−324 to to ±±1.71.7 ×× 1010308308): 64): 64--bits, bits,

precision of 15precision of 15--16 digits16 digits

�� The default value of floatingThe default value of floating--point types:point types:

�� Is Is 0.0F0.0F for the for the floatfloat typetype

�� Is Is 0.0D0.0D for the for the doubledouble typetype

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PI Precision PI Precision –– ExampleExample

�� See below the See below the difference in precision when using difference in precision when using

floatfloatand and doubledouble::

�� NOTE: The NOTE: The ““ff” ” suffix in the first statement!suffix in the first statement!

�� Real numbers are by default interpreted as Real numbers are by default interpreted as doubledouble!!

�� One should One should explicitlyexplicitly convert them to convert them to floatfloat

float floatPI = 3.141592653589793238f;float floatPI = 3.141592653589793238f;

double doublePI = 3.141592653589793238;double doublePI = 3.141592653589793238;

Console.WriteLine("Float PI is: {0}", floatPI);Console.WriteLine("Float PI is: {0}", floatPI);

Console.WriteLine("Double PI is: {0}", doublePI);Console.WriteLine("Double PI is: {0}", doublePI);

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Abnormalities Abnormalities in the in the FloatingFloating--Point CalculationsPoint Calculations

�� Sometimes abnormalities Sometimes abnormalities can be observed can be observed when using floatingwhen using floating--point numberspoint numbers

�� Comparing floatingComparing floating--point numbers can not be point numbers can not be

performed directly performed directly with with the the ==== operatoroperator


double a = 1.0f;double a = 1.0f;

double b = 0.33f;double b = 0.33f;

double sum = 1.33f;double sum = 1.33f;

bool equal = (a+b == sum); // False!!!bool equal = (a+b == sum); // False!!!

Console.WriteLine("a+b={0} sum={1} equal={2}",Console.WriteLine("a+b={0} sum={1} equal={2}",

a+b, sum, equal);a+b, sum, equal);

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Decimal FloatingDecimal Floating--Point Point TypesTypes

�� There is a special There is a special decimal floatingdecimal floating--pointpointreal real number number type in C#:type in C#:

�� decimaldecimal ((±±1,01,0 ×× 1010--2828 to to ±±7,97,9 ×× 10102828): 128): 128--bits, bits,

precision of 28precision of 28--29 digits29 digits

�� Used for financial Used for financial calculationscalculations

�� No roundNo round--off off errorserrors

�� Almost no loss of precisionAlmost no loss of precision

�� The default value of The default value of decimaldecimal type is:type is:

�� 0.00.0MM ((MM is the suffix for decimal numbers)is the suffix for decimal numbers)

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FloatingFloating--Point and Decimal Point and Decimal FloatingFloating--Point TypesPoint Types

Example 02Example 02--03;0203;02--0404

Boolean TypeBoolean Type

The Boolean Data TypeThe Boolean Data Type

�� The The Boolean Boolean data typedata type::

�� Is declared Is declared by by the the boolbool keywordkeyword

�� Has two possible valuesHas two possible values: : truetrue and and falsefalse

�� Is useful in logical expressionsIs useful in logical expressions

�� The default value is The default value is falsefalse

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Boolean Values Boolean Values –– ExampleExample

�� Example of boolean Example of boolean variables variables taking taking values of values of truetrueor or falsefalse::

int a = 1;int a = 1;

int b = 2;int b = 2;

bool bool greaterAB = (a > b);greaterAB = (a > b);

Console.WriteLine(greaterAB); // FalseConsole.WriteLine(greaterAB); // False

bool bool equalA1 = (a == 1);equalA1 = (a == 1);

Console.WriteLine(equalA1); // TrueConsole.WriteLine(equalA1); // True

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Boolean TypeBoolean TypeExample 02Example 02--05; 0205; 02--0606

Character TypeCharacter Type

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The Character Data TypeThe Character Data Type

�� The The character data typecharacter data type::

�� Represents symbolic informationRepresents symbolic information

�� Is declared by the Is declared by the charchar keywordkeyword

�� Gives each symbol a corresponding integer codeGives each symbol a corresponding integer code

�� Has a Has a ''\\0'0' default valuedefault value

�� Takes 16 bits of memory (from Takes 16 bits of memory (from U+0000U+0000 to to

U+FFFFU+FFFF))

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Characters Characters and and CodesCodes

�� The example below shows that every The example below shows that every symbol symbol has an has an its unique Unicode codeits unique Unicode code::

char symbol = 'a';char symbol = 'a';

Console.WriteLine("The code of '{0}' is: {1}",Console.WriteLine("The code of '{0}' is: {1}",

symbol, (symbol, (intint) symbol) symbol););

symbol symbol = = 'b';'b';


symbol, (symbol, (intint) symbol);) symbol);

symbol symbol = = 'A';'A';


symbol, (symbol, (intint) symbol) symbol););

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Character TypeCharacter TypeExample 02Example 02--0707

String TypeString Type

The String Data TypeThe String Data Type

�� The The string data typestring data type::

�� Represents a sequence of charactersRepresents a sequence of characters

�� Is declared by the Is declared by the stringstring keywordkeyword

�� Has a default value Has a default value nullnull (no value)(no value)

�� Strings are enclosed in quotes:Strings are enclosed in quotes:

�� Strings can be Strings can be concatenatedconcatenated

�� Using the Using the ++ operatoroperator

string string s s = = "Microsoft .NET Framework";"Microsoft .NET Framework";

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Saying Saying Hello Hello –– ExampleExample

�� Concatenating Concatenating the two names of a person to the two names of a person to obtain obtain his full name:his full name:

�� NOTE: a space is missing between the two NOTE: a space is missing between the two

names! We have to add it manuallynames! We have to add it manually

string firstName = "Ivan";string firstName = "Ivan";

string lastName = "Ivanov";string lastName = "Ivanov";

Console.WriteLine("Hello, {0Console.WriteLine("Hello, {0}!}!\\n", n", firstName);firstName);

string fullName = firstName + string fullName = firstName + " " + lastName" " + lastName;;

Console.WriteLine("Your full name is {0Console.WriteLine("Your full name is {0}.",}.",

fullNamefullName););

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String TypeString TypeExample 02Example 02--08;0208;02--0909

Object TypeObject Type

The Object TypeThe Object Type

�� The object type:The object type:

�� Is declared by the Is declared by the objectobject keywordkeyword

�� Is the Is the base type base type of all other typesof all other types

�� Can Can hold values of any typehold values of any type

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Using ObjectsUsing Objects

�� Example Example of an object variable taking different of an object variable taking different types of data:types of data:

object dataContainer = 5;object dataContainer = 5;

Console.Write("The value of dataContainer Console.Write("The value of dataContainer is: ");is: ");

Console.WriteLine(dataContainer);Console.WriteLine(dataContainer);

dataContainer = "Five";dataContainer = "Five";

Console.Write("Console.Write("The value of dataContainer The value of dataContainer is: ");is: ");

Console.WriteLine(dataContainer);Console.WriteLine(dataContainer);

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ObjectsObjectsExample 02Example 02--1010

Introducing VariablesIntroducing Variables

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What Is a Variable?What Is a Variable?

�� A variable is a:A variable is a:

�� Placeholder of information that can usually Placeholder of information that can usually be be

changed changed at runat run--timetime

�� Variables allow you to:Variables allow you to:

�� Store informationStore information

�� Retrieve the stored informationRetrieve the stored information

�� Manipulate the stored informationManipulate the stored information

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Variable CharacteristicsVariable Characteristics

�� A variable has:A variable has:

�� NameName

�� Type (of stored data)Type (of stored data)

�� ValueValue


�� Name: Name: countercounter

�� Type: Type: intint

�� Value: Value: 55

int counter = 5;int counter = 5;

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Declaring And Using Declaring And Using

VariablesVariables

Declaring VariablesDeclaring Variables

�� When declaring a variable we:When declaring a variable we:

�� Specify its typeSpecify its type

�� Specify its name (called identifier)Specify its name (called identifier)

�� May give it an initial valueMay give it an initial value

�� The syntax is the following:The syntax is the following:


<data_type> <identifier> [= <initialization>];<data_type> <identifier> [= <initialization>];

int height = 200;int height = 200;

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IdentifiersIdentifiers

�� Identifiers may consist of:Identifiers may consist of:

�� Letters (Unicode) Letters (Unicode)

�� Digits [0Digits [0--9]9]

�� Underscore "_"Underscore "_"


�� Can begin only with a letter or an underscoreCan begin only with a letter or an underscore

�� Cannot be a C# keywordCannot be a C# keyword

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Identifiers (2)Identifiers (2)


�� Should Should have a have a descriptive namedescriptive name

�� It is recommended to use only Latin lettersIt is recommended to use only Latin letters

�� Should be neither too long nor too shortShould be neither too long nor too short

�� Note:Note:

�� In C# small In C# small letters are considered different than letters are considered different than

the capital the capital letters (case sensitivity)letters (case sensitivity)

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Identifiers Identifiers –– ExamplesExamples

�� Examples of Examples of correct identifierscorrect identifiers::

�� Examples of incorrect identifiers:Examples of incorrect identifiers:

int new;int new; // new // new is a keywordis a keyword

int int 2Pac;2Pac; // Cannot // Cannot begin with a digitbegin with a digit

int New = 2int New = 2; // Here ; // Here N is capitalN is capital

int _int _2Pac; // This 2Pac; // This identifiers begins with _identifiers begins with _

string string üşrtüşrt = "Hello"; = "Hello"; // Unicode // Unicode symbols usedsymbols used

// The // The following is more appropriate:following is more appropriate:

string greeting = "Hello"; string greeting = "Hello";

int int n = 100n = 100; // Undescriptive; // Undescriptive

int numberOfClients = 100int numberOfClients = 100; // Descriptive; // Descriptive

// Overdescriptive // Overdescriptive identifier:identifier:

int numberOfPrivateClientOfTheFirm = 100;int numberOfPrivateClientOfTheFirm = 100;

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Assigning Values Assigning Values

To VariablesTo Variables

Assigning ValuesAssigning Values

�� Assigning of Assigning of values values to to variablesvariables

�� Is achieved by the Is achieved by the == operatoroperator

�� The The == operator hasoperator has

�� Variable identifier on the leftVariable identifier on the left

�� Value of the corresponding data type on the Value of the corresponding data type on the

rightright

�� Could be used in a cascade calling, where Could be used in a cascade calling, where

assigning is done from right to leftassigning is done from right to left

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Assigning Values Assigning Values –– ExamplesExamples

�� Assigning values example:Assigning values example:

int firstValue = 5;int firstValue = 5;

int secondValue;int secondValue;

int thirdValue;int thirdValue;

// Using // Using an already an already declared declared variable:variable:

secondValue = firstValue;secondValue = firstValue;

// The // The following cascade calling assignsfollowing cascade calling assigns

// 3 // 3 to firstValue and then firstValueto firstValue and then firstValue

// to // to thirdValue, so both variables havethirdValue, so both variables have

// the // the value 3 as a resultvalue 3 as a result::

thirdValue = firstValue = 3thirdValue = firstValue = 3; // Avoid this!; // Avoid this!

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Initializing VariablesInitializing Variables

�� InitializingInitializing

�� Is assigning of initial valueIs assigning of initial value

�� Must be done before the variable is used!Must be done before the variable is used!

�� Several ways of initializing:Several ways of initializing:

�� By using the By using the newnew keywordkeyword

�� By using a literal expressionBy using a literal expression

�� By referring to an already initialized variableBy referring to an already initialized variable

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Initialization Initialization –– ExamplesExamples

�� Example Example of some initializations:of some initializations:

// The // The following would assign the defaultfollowing would assign the default

// value // value of the int type to num:of the int type to num:

int num = new intint num = new int(); // num = 0(); // num = 0

// This // This is how we use a literal expression:is how we use a literal expression:

float heightInMeters = 1.74f;float heightInMeters = 1.74f;

// Here // Here we use an already initialized variable:we use an already initialized variable:

string greeting = "Hello World!";string greeting = "Hello World!";

string message = greeting;string message = greeting;

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LiteralsLiterals

What What are Literals?are Literals?

�� Literals are:Literals are:

�� Representations Representations of of values in the source codevalues in the source code

�� There are six types of literalsThere are six types of literals

�� BooleanBoolean

�� IntegerInteger

�� RealReal

�� CharacterCharacter

�� StringString

�� The The nullnull literalliteral50

Boolean and Integer LiteralsBoolean and Integer Literals

�� The boolean literals are:The boolean literals are:

�� truetrue

�� falsefalse

�� The integer literals:The integer literals:

�� Are used for variables of type Are used for variables of type intint, , uintuint, , longlong, , and and ulongulong

�� Consist of digitsConsist of digits

�� May have a sign (May have a sign (++,,--))

�� May be in a hexadecimal formatMay be in a hexadecimal format

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Integer LiteralsInteger Literals

�� Examples of integer literalsExamples of integer literals

�� The The ''0x0x'' and and ''0X0X'' prefixes prefixes mean a mean a

hexadecimal value, e.g. hexadecimal value, e.g. 0xA8F10xA8F1

�� The The ''uu'' and and ''UU'' suffixes suffixes mean a mean a ulongulongor or uintuint

type, e.g. type, e.g. 12345678U12345678U

�� The The ''ll'' and and ''LL'' suffixes suffixes mean a mean a longlong or or ulongulong

type, e.g. type, e.g. 9876543L9876543L

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Integer Literals Integer Literals –– ExampleExample

�� Note: the letter ‘Note: the letter ‘ll’ is easily confused with the ’ is easily confused with the digit ‘digit ‘11’ so it’s better to use ‘’ so it’s better to use ‘LL’!!!’!!!

// The // The following following variables arevariables are

// initialized // initialized with the same value:with the same value:

int numberInHex = int numberInHex = --0x10;0x10;

int numberInDec = int numberInDec = --16;16;

// The // The following causes an error,following causes an error,

because 234u is of type uintbecause 234u is of type uint

int unsignedInt = 234u;int unsignedInt = 234u;

// The // The following causes an error,following causes an error,

because 234L is of type longbecause 234L is of type long

int longInt = 234L;int longInt = 234L;

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Real LiteralsReal Literals

�� The real literals:The real literals:

�� Are used for values of type Are used for values of type floatfloat, , doubledoubleand and

decimaldecimal

�� May consist of digits, a sign and May consist of digits, a sign and ““..””

�� May be in exponential May be in exponential notation: notation: 6.02e+236.02e+23

�� The The ““ff” ” and and ““FF” ” suffixes mean suffixes mean floatfloat

�� The “The “dd” and “” and “DD” suffixes mean ” suffixes mean doubledouble

�� The “The “mm” and “” and “MM” suffixes mean ” suffixes mean decimaldecimal

�� The The default interpretation is default interpretation is doubledouble54

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Real Literals Real Literals –– ExampleExample

�� Example of incorrect Example of incorrect floatfloat literal:literal:

�� A correct way to assign floatingA correct way to assign floating--point value point value (using also the exponential format):(using also the exponential format):

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// The // The following causes an errorfollowing causes an error

// because // because 12.5 is double by default12.5 is double by default

float realNumber = 12.5;float realNumber = 12.5;

// The // The following is the correctfollowing is the correct

// way // way of assigning the value:of assigning the value:

float realNumber = 12.5f;float realNumber = 12.5f;

// This // This is the same value in exponential format:is the same value in exponential format:

realNumber = realNumber = 1.25e+7f;1.25e+7f;

Character LiteralsCharacter Literals

�� The character literals:The character literals:

�� Are used for values of the Are used for values of the charchar typetype

�� Consist of two single quotes surrounding the Consist of two single quotes surrounding the

character valuecharacter value: : ''<value><value>''

�� The value may be:The value may be:

�� SymbolSymbol

�� The code of the symbolThe code of the symbol

�� Escaping Escaping sequencesequence

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Escaping SequencesEscaping Sequences

�� Escaping Escaping sequences are:sequences are:

�� Means of presenting a symbol that is usually Means of presenting a symbol that is usually

interpreted otherwise (like interpreted otherwise (like ''))

�� Means of presenting system symbols (like the Means of presenting system symbols (like the

new line symbol)new line symbol)

�� Common Common escaping escaping sequences are:sequences are:

�� \\'' for single for single quotequote \\"" for double quotefor double quote

�� \\\\ for for backslashbackslash \\nn for new for new lineline

�� \\uXXXXuXXXX for denoting any other Unicode symbolfor denoting any other Unicode symbol

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Character Literals Character Literals –– ExampleExample

�� Examples of different character literals:Examples of different character literals:

char symbol = 'a'; // An ordinary symbolchar symbol = 'a'; // An ordinary symbol

symbol = 'symbol = '\\u006F'; // Unicode symbol code in u006F'; // Unicode symbol code in

// a hexadecimal format// a hexadecimal format

symbol = 'symbol = '\\u8449'; // u8449'; // 葉葉葉葉葉葉葉葉 ((Leaf in Traditional Chinese)Leaf in Traditional Chinese)

symbol = 'symbol = '\\''; // Assigning the single quote symbol''; // Assigning the single quote symbol

symbol = 'symbol = '\\\\'; // Assigning the backslash symbol'; // Assigning the backslash symbol

symbol = 'symbol = '\\n'; // Assigning new line symboln'; // Assigning new line symbol

symbol = 'symbol = '\\t'; // Assigning TAB symbolt'; // Assigning TAB symbol

symbol = "a"; // Incorrect: use single quotessymbol = "a"; // Incorrect: use single quotes

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String LiteralsString Literals

�� String literals:String literals:

�� Are used for values of the string typeAre used for values of the string type

�� Consist of two double quotes surrounding the Consist of two double quotes surrounding the

value: value: ""<value><value>""

�� May have a May have a @@ prefix which prefix which ignores the ignores the used used

escaping sequences: escaping sequences: @@"<value>""<value>"

�� The value is a sequence of character literalsThe value is a sequence of character literals

string s = "I am a sting literal";string s = "I am a sting literal";

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String Literals String Literals –– ExampleExample

�� Benefits of quoted strings (the Benefits of quoted strings (the @@ prefix):prefix):

�� In quoted strings In quoted strings \\"" is used instead of is used instead of """"!!

// Here // Here is a string literal using escape sequencesis a string literal using escape sequences

string quotation = "string quotation = "\\"Hello, Jude"Hello, Jude\\", he said.";", he said.";

string path = "C:string path = "C:\\\\WINNTWINNT\\\\DartsDarts\\\\Darts.exe";Darts.exe";

// Here // Here is an example of the usage of @is an example of the usage of @

quotation = @"""Hello, Jimmy!"", she answered.";quotation = @"""Hello, Jimmy!"", she answered.";

path = @"C:path = @"C:\\WINNTWINNT\\DartsDarts\\Darts.exeDarts.exe";";

string str = @"somestring str = @"some

text";text";

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String LiteralsString LiteralsExample 02Example 02--1111

Nullable TypesNullable Types

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Nullable TypesNullable Types

�� NullableNullable types are instances of the types are instances of the System.NullableSystem.Nullable structstruct

�� Wrapper over the Wrapper over the primitiveprimitive typestypes

�� E.g. E.g. int?int?, , double?double?, , etc.etc.

�� NullabeNullabe type can represent the normal range type can represent the normal range of values for its underlying value type, plus an of values for its underlying value type, plus an additional additional nullnull valuevalue

�� Useful when dealing with Useful when dealing with DatabasesDatabasesor other or other structures that have default value structures that have default value nullnull

Nullable Types Nullable Types –– ExampleExample

int? someInteger = null;int? someInteger = null;

Console.WriteLine(Console.WriteLine("This is the integer with Null value "This is the integer with Null value --> " + someInteger);> " + someInteger);

someInteger = 5;someInteger = 5;

Console.WriteLineConsole.WriteLine(("This "This is the integer is the integer with with value value 5 5 --> " + someInteger);> " + someInteger);

double? someDouble = null;double? someDouble = null;

Console.WriteLine(Console.WriteLine("This is the real number with Null value "This is the real number with Null value --> " > "

+ someDouble);+ someDouble);

someDouble = 2.5;someDouble = 2.5;Console.WriteLine(Console.WriteLine(

"This is the real number with value 5 "This is the real number with value 5 --> " + > " +

someDouble);someDouble);

Example with Example with IntegerInteger::

Example with Example with DoubleDouble::

Nullable TypesNullable TypesExample 02Example 02--1212

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Questions?Questions?

Primitive Data Primitive Data Types and VariablesTypes and Variables

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ExercisesExercises

1.1. Declare five variables choosing for each of them the Declare five variables choosing for each of them the

most appropriate of the types most appropriate of the types bytebyte, , sbytesbyte, , shortshort, ,

ushortushort, , intint, , uintuint, , longlong, , ulongulong to represent the to represent the

following values: 52130, following values: 52130, --115, 4825932, 97, 115, 4825932, 97, --10000.10000.

2.2. Which of the following values can be assigned to a Which of the following values can be assigned to a

variable of type variable of type floatfloatand which to a variable of and which to a variable of

type type doubledouble: 34.567839023, 12.345, 8923.1234857, : 34.567839023, 12.345, 8923.1234857,

3456.091?3456.091?

3.3. Write a program that Write a program that safely safely compares compares floatingfloating--point point

numbers with precision of numbers with precision of 0.0000010.000001..

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Exercises (2)Exercises (2)

4.4. Declare an integer variable and assign it with the Declare an integer variable and assign it with the

value value 254 254 in hexadecimal in hexadecimal format. Use Windows format. Use Windows

Calculator to find its hexadecimal representation.Calculator to find its hexadecimal representation.

5.5. Declare a character variable and assign it with the Declare a character variable and assign it with the

symbol symbol that has Unicode code 72. Hint: first use the that has Unicode code 72. Hint: first use the

Windows Calculator to find the hexadecimal Windows Calculator to find the hexadecimal

representation of 72.representation of 72.

6.6. Declare a boolean variable called Declare a boolean variable called isFemaleisFemaleand and

assign an appropriate value corresponding to your assign an appropriate value corresponding to your

gender.gender.

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7.7. Declare two Declare two stringstringvariables and assign them with variables and assign them with

“Hello” and “World”. Declare an “Hello” and “World”. Declare an objectobjectvariable and variable and

assign it with the concatenation of the first two assign it with the concatenation of the first two

variables (mind adding an interval). variables (mind adding an interval). Declare a third Declare a third

stringstringvariable and initialize it with the value of the variable and initialize it with the value of the

object object variable (you variable (you should perform type casting).should perform type casting).

8.8. Declare two Declare two stringstringvariables and assign them with variables and assign them with

following value:following value:

Do the above in two different Do the above in two different ways: with and ways: with and

without using quoted strings.without using quoted strings.

The "use" of quotations causes difficulties. The "use" of quotations causes difficulties.

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9.9. Write a program thatWrite a program that prints an isosceles triangle of prints an isosceles triangle of 9 9 copyright symbols copyright symbols ©©. Use Windows Character . Use Windows Character Map to find the Unicode code of the Map to find the Unicode code of the ©© symbol.symbol.

10.10. A marketing firm wants to keep record of its A marketing firm wants to keep record of its employees. Each record would have the following employees. Each record would have the following characteristics characteristics –– first name, family name,first name, family name, age,age,gender (m or f), ID number,gender (m or f), ID number, unique employee unique employee number (27560000 to 27569999). Declare the number (27560000 to 27569999). Declare the variables needed to keep the information for a variables needed to keep the information for a single employee using appropriate data typessingle employee using appropriate data types andanddescriptive namesdescriptive names..

11.11. Declare two integer variables and assign them with Declare two integer variables and assign them with 5 and 10 and after that exchange their values.5 and 10 and after that exchange their values.

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11.. primitive data types and variables - eemb · pdf file10/3/2011 1 primitive data types and...

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