Review 1

Computers and Programming IDr. Ming Zhang

Tel: (757) 594-7065Fax: (757) 594-7919Office: Gosnold 217b Email: mzhang@cnu.edu Subject Overview Dr. Ming Zhang

Algorithms* Definition of AlgorithmAn algorithm is defined as a step-by-step sequence of instructions that must terminate and describes how the data is to be processed to produce the desired outputs

* Question for Developing an AlgorithmIn essence, an algorithm answers the question, What method will you use to solve this problem? Introduction to Computers and Programming Dr. Ming Zhang

Flowchart for Calculating the Average 1

Start

Input values for a, b, and c

Calculate the average

Display the average

End Introduction to Computers and Programming Dr. Ming Zhang

Hollow World Using C++#include using std::cout; // program uses coutusing std:cin; // Program uses cinusing std:endl; // program uses endlint main ( ){cout

Three Basic Data Values* Integer Numbers - Valid: 0, 5, -10, +25, 1000, 253, -26351, +36- Invalid: $255.62, 2,523, 3., 6,234,892, +6.0

* Floating-Point Numbers- Valid: +10.625, 5., -6.2, 0.0, 0.33, -6.67, +2.- Invalid: 5,326.25, 24, 123, 6,459, $10.29

* Character Values- Valid: A, $, b, 7, y, Y, M, q Problem Solving Using C Dr. Ming Zhang

Arithmetic OperationsOperation Operator Type Associativity

Addition+ BinaryLeft to rightSubtraction- BinaryLeft to rightMultiplication* BinaryLeft to rightDivision/ BinaryLeft to rightModulus % BinaryLeft to rightNegation- UnaryRight to Left

Problem Solving Using C Dr. Ming Zhang

Assignment Operations* General Form of Assignment Statementvariable = operand;* Constant Operand for Assignmentlength = 25; (is read, length is assigned the value 25) * Overwritten with New Valuelength = 25;length = 6.28;( The 25 that was in length is overwritten with new value of 6.28, because a variable can only store one value at a time) Completing the Basic Dr. Ming Zhang

Assignment Variations* Assignment VariationsThe variable on the left of the equal sign can also be used the right of the equal sign in the assignment statement sum = 20; sum = sum +10; /* sum = 30 */* Assignment expressions like sum = sum + 25, which use the same variable on both sides of the assignment operator, can be written using the following assignment operators: += -= *= %= Completing the Basic Dr. Ming Zhang

Mathematical Library FunctionsFunction Name & Argument(s) Descriptionint abs(int i) Absolute value of idouble fabs(double d) Absolute value of ddouble pow(double d1, double d2) d1 raised to d2 powerdouble exp(double d) e raised to d powerdouble sqrt(doubler d) square root of ddouble sin(double d) Sin of d(d in radians)double cos(double d) Cosine of d(d: radians)double log(double d) Natural log of ddouble log10(double d) Common log of d Completing the Basic Dr. Ming Zhang

Relational Operators

Operator Meaning Example < Less thanage < 30>Greater than hight > 6.2= 98.6==Equal to grade == 100!=Not equal tonumber !=250 Selection Control Structure Dr. Ming Zhang

Logical Operators* Logical Operators&&: Logical operator AND||: Logical operator OR!: Logical operator NOT* Examples- (age > 40) && (term < 10)is true only if age is greater than 40 and term is less 10.- (age > 40) || (term < 10)will be true if either age is greater than 40, term is less 10, or both condition are true. Selection Control Structure Dr. Ming Zhang

If Statement* Syntax of if Statementif (condition)statement executed if condition is true

* General Form of if Statement if (expression)statement; Selection Control Structure Dr. Ming Zhang

If-else Statement* Syntax of if-else Statementif (condition)statement executed if condition id trueelsestatement executed if condition is false

* General Form of if-else Statement if (expression)statement1;elsestatement2; Selection Control Structure Dr. Ming Zhang

Nested if Statement* The inclusion of one or more if statements whthin an existing if statement is called a nested if statement.* if ( expression1) { if (expression2) statement 1; } else Statement3; Selection Control Structure Dr. Ming Zhang

if-else Nested within the if partif ( expression1) { if (expression2) statement 1; else statement 2; } else Statement3; Selection Control Structure Dr. Ming Zhang

if-else Nested within the else partif ( expression1)statement 1; else if (expression2) statement2;elsestatement3; Selection Control Structure Dr. Ming Zhang

Exercise: if-else Chain (C ++)#include using std::cout; using std::endl; using std::cin;int main( ){char marcode;cout > marcode;if (marcode == M) cout

Pseudocode* Pseudocode Pseudocode is an artificial and informal language that helps programmers develop algorithm. Pseudocode is simular to everyday English.* Pseudocode consists only of executable statements - those that are executed when the program has been converted from pseudocode to C++ and is run.( no declaration part) Dr. Ming Zhang

while LoopEnter the while statement

Test the Expression = 0 expression exit Step 1 whileLoop Expression != 0 Execute the statement after the parentheses (step 2a) Go back and reevaluate the express (step 2b) Dr. Ming Zhang

Top-Down Stepwise Refinement* The top is a single statement that conveys the overall function of the program.* Then we divided the top into a series of smaller tasks and list these in the order in which they need to be performed. This results the first refinement.* To proceed to the next level of refinement until no further level refinement could be taken. Dr. Ming Zhang

Cast Operator static_cast* Cast Operator static_cast creates a temporary floating-point copy of its operand in parentheses - total.* Using a cast operator in this manner is called explicit conversion.* The value stored in total is still an integer.* The calculation now consists of a floating-point value (the temporary float version of total) Dr. Ming Zhang

Promotion* The C++ compiler only knows to evaluate expressions in which the data types of the operands are identical.* To ensure that the operands are of the same type, the compiler performs an operation called promotion(also called implicit conversion) on selection operands.* For example, in an expression containing the data types int and float, int operands are promoted to float. Dr. Ming Zhang

setiosflags(ios::fixed|iso::showpoint)* The stream manipulator setiosflags(ios::fixed|iso::showpoint)sets two output formatting options, namely ios::fixed and iso::showpoint.

* The vertical bar character ( | ) separates multiple options in a setiosflags call. Dr. Ming Zhang

ios::fixed* The option ios::fixed causes a floating-point value to be output in so-called fixed-point format (such as 92.34), not the scientific notation (such as 9.23e+1).

* Fixed-Point Format Scientific Notation234.56 2.3456e+20.00479 4.79e-3 Dr. Ming Zhang

iso::showpoint* The option iso::showpoint forces the decimal point and trailing zero to print even if the value is a whole number amount (such as 88.00).* Without the option iso::showpoint, such a value prints in C++ as 88 without the trailing zero and without the decimal point.* The printed value is rounded to indicated number of decimal positions, although the value in the memory remains unaltered. Dr. Ming Zhang

Condition Operator (?:)* Conditional Operator (?:) - Ternary Operator Operand1 ? Operand2 : Operand3* First Operand Condition Expression* Second Operandthe value for the entire conditional expression if the condition is true.* Third Operandthe value for the entire conditional expression if the condition is false. Dr. Ming Zhang

Preincrement and Postincrement* Preincrement ++a Increment a by 1, then use the new value of a in the expression in which a resides.

* Postincrement a++ Use the current value of a in the expression in which a resides, then increment a by 1 Dr. Ming Zhang

Predecrement and Postdecrement* Predecrement --a Decrement a by 1, then use the new value of a in the expression in which a resides.

* Postdecrement a-- Use the current value of a in the expression in which a resides, then decrement a by 1 Dr. Ming Zhang

A for Loop Flowchart Initializing Statement(s)

Evaluate false the tested exit expression for Loop true Execute the statement after the parentheses

Execute the altering list Dr. Ming Zhang

Pre/Postincrement of the Counter* Postincrement of the Counterfor (int counter = 1; counter

Stream Manipulator setw(m)* The call setw(m) specifies that the next value output is printed in filed width of m. * If the value to be output is less than m character positions wide, the value is right justified in the filed by default.* If the value to be output is more than m character position wide, the field width is extended to accommodate the entire value. Dr. Ming Zhang

Flowchart of switch Statement

case a case a action(s) break

case b case b action(s) break ....... case z case z action(s) break

default action(s)

Dr. Ming Zhang

cin.get

* grade = cin.getThe cin.get( ) function reads one character from the keyboard and stores that character in integer variable grade.

* Details will be introduced in Chapter 6, Classes.

Dr. Ming Zhang

EOF * EOF (end-of-file)EOF is the symbol whose acronym stands for end-of-file.* EOF normal has the value -1. However, we do not type the value -1 nor do we type the letters EOF. Rather, you type a system-dependent keystroke combination to mean end-of-file.* UNIX: -> EOF MS-DOS: -> EOF Dr. Ming Zhang

Flowchart of do/while StructureEnter do/while statement

Execute the statement(s)after do exit the Loop false doEvaluate the statementexpression true Dr. Ming Zhang

break Statement* The break statement, when executed in a while, for, do/while, or switch structure, causes immediate exit for that structure.* Program execution continues with the first statement after the structure.* Common uses of the break statement are to escape early from a loop, or to skip the remainder of a switch structure Dr. Ming Zhang

Continue Statement* The continue statement, when executed in a while, for, or do/while structure, skips the remaining statements in the body of that structure, and proceeds with the next iteration of the loop. * In while and do/while structures, the loop-continuation test is evaluated immediately after the continue statement is executed.* In the for structure, the increment expression is executed, then the loop-continuation test is evaluated. Dr. Ming Zhang

Interactive Input within a Loop#include #define MAX 5using std::cout; using std::cin;int main( ){int count, num; float total, average;for(total=0.0,count=1;count num; total = total + num;} average = total/MAX; cout

Selection within a Loop#include #define MAX 5#define THR 8using std::cout; using std::cin;int main( ){int count, num; float total, average;for(total=0.0,count=1;count num; if(num> THR) total = total + num; else total = total - num;} average = total/MAX; cout

Evaluating Functions of One Variable# include using std::cout; using std::endl;int main( ){ int x, y;for (x=2; x

Interactive Loop Control#include using std::cout; using std::endl;int main( ){ int num, final;cout

Exercises/Home Work

You should studyALL questions from the Exercises and Home Work !!! Dr. Ming Zhang

Test 1

Week 6, Monday, 20%

Good Luck!!! Dr. Ming Zhang