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CSC-201 - Computer Science ILecture #10: Chapter 10 concluded, Chapter 11

started

Dr. Chuck CartledgeDr. Chuck CartledgeDr. Chuck CartledgeDr. Chuck CartledgeDr. Chuck CartledgeDr. Chuck CartledgeDr. Chuck CartledgeDr. Chuck CartledgeDr. Chuck CartledgeDr. Chuck CartledgeDr. Chuck CartledgeDr. Chuck CartledgeDr. Chuck CartledgeDr. Chuck CartledgeDr. Chuck CartledgeDr. Chuck CartledgeDr. Chuck CartledgeDr. Chuck CartledgeDr. Chuck CartledgeDr. Chuck CartledgeDr. Chuck Cartledge

October 24, 2016 at 11:01pmOctober 24, 2016 at 11:01pmOctober 24, 2016 at 11:01pmOctober 24, 2016 at 11:01pmOctober 24, 2016 at 11:01pmOctober 24, 2016 at 11:01pmOctober 24, 2016 at 11:01pmOctober 24, 2016 at 11:01pmOctober 24, 2016 at 11:01pmOctober 24, 2016 at 11:01pmOctober 24, 2016 at 11:01pmOctober 24, 2016 at 11:01pmOctober 24, 2016 at 11:01pmOctober 24, 2016 at 11:01pmOctober 24, 2016 at 11:01pmOctober 24, 2016 at 11:01pmOctober 24, 2016 at 11:01pmOctober 24, 2016 at 11:01pmOctober 24, 2016 at 11:01pmOctober 24, 2016 at 11:01pmOctober 24, 2016 at 11:01pm

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Table of contents I

1 Schedule

2 Miscellanea

3 Chap. 10

4 Chapter 11

5 Break

6 Hands on

7 Q & A

8 Conclusion

9 References

10 Files

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Schedule for the semester:

Wk. Date Topic Wk. Date Topic1 08/22 Chaps. 1 2 X 9 10/17 Chap. 10 X2 08/29 Chaps. 3 4 X 10 10/24 Chaps. 10 113 09/05 Chap. 5 X 11 10/31 Chaps. 10 114 09/12 Test Chap. 6 X 12 11/07 Test Chap. 145 09/19 Chap. 7 X1 13 11/14 Chap. 146 09/26 Chap. 8 X 14 11/28 Chap. 187 10/03 Chap. 9 X 15 12/05 Chap. 188 10/10 Test Chap. 10 X 16 12/12 Exam

Notes:

1 Class canceled due to electrical fire in instructors home

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Programming assignment #004

File Based Address Book

Objectives are fairly straightforward:

Accept two new commands fromthe user

Commands are:

+ to add a new contact- to remove all contacts that

match a search string

Update the data file with new, orremoved contacts

Submit your source code.

This is a single person effort (not ateam effort).

Due by start of class 26 Oct. 2016.

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Programming assignment #005

Internal Array Based Address Book

Objectives are fairly straightforward:

Maintain all the capability fromprogramming assignment #004

Output matching search contactsalphabetized by last name

Support up to 1,000 contacts

Use an array of structures to dothe work

This is a single person effort (not ateam effort).

Due by start of class 9 Nov. 2016.

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Programming assignment #005

Q & A time.

Q: How was Thomas J. Watsonburied?A: 9 edge down.

Now is the time to ask questions.

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Corrections and additions since last lecture.

Wrote up programmingassignment #005

Took life easy.

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A review

A quick review

1 There are complex, userdefined types (UDT) calledstructs

2 A struct is a way to referto multiple variables by thesame name

3 A struct can contain otherstructs

4 You access a structmember using the dotoperator

5 A struct has aggregate andmember operations

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A review

Continuing onto other data types

Today looking at:

1 union where multipleidentifiers point to the samememory location

2 pointer and referencewhere we can look atmemory directly

Image from [1].

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Memory

Some basics about memory

It all comes down toidentifiers and how to createthem, how to use them, andhow they can be misused.

Well see some of this duringHands On.There are lots of things you cando with identifiers.

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Memory

The basics about pointers

An identifier can:

Contain the thing/variabledirectly, or

Contain the memory addressof the thing (called apointer), or

Contain the memory addressof the memory address ofthe . . .

Well play with these in the addresses.cpp program.

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Memory

Some pointer details. You can:

Declare a variableint i;

Declare a pointer to a type ofvariableint* intPtr;

Assign a value to a variablei = 12;

Assign the location of a variableto a pointerintPtr = &i;

Change the contents of a memorylocation*intPtr = 13;

Change where to make changes inmemoryintPtr ++;

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Memory

Types of expressions

Arithmetic expressions are made up of variables, constants,operators, and parenthesis.

Pointer expressions are composed of pointer variables,pointer constants, pointer operators, and parenthesis.

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Memory

Pointers can point to ANYTHING.

Pointers can point to:

Variables (well see this in the hands on)

Structures (structs are just a collection of variables)

Functions (well see this in the hands on)

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Memory

Pointers and structs

To access a member of a struct, we use the dot operator (.)To access a variable using a pointer, we use the dereferenceoperator (*)To access a member of a struct, we have two choices:

1 Combine the dereference operator and the dot operator(*patientPtr).weight = 160;

2 Combine the arrow operator with the dot operatorpatientPtr >weight = 160;

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Memory

Variations on a theme

Pointers and reference type variables:

Pointer type variables contain the address of a variableint* intPtr;

Reference type variables contain the address of a variableint& intPtr;

Both contain the address of a variable

Differences:

Pointers require the dereference operator (*) and the addressoperator (&) to get the address of the variableReferences do this automatically (i.e., the compiler knowsyou are working with a reference type and inserts operators asnecessary)

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One dimensional arrays

Continuing onto other data types (again)

Now diving into areas where arethe variables are the same type.

1 Declaring and using onedimensional arrays

2 Passing arrays to functions

Image from [1].

One dimesional arrays are sometimes called vectors.

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One dimensional arrays

Common thread through the structured data types

1 Structured data type stores a collection of individualcomponents (sometimes called members) as part of a singlevariable name

2 Individual components (or members) can be accessed, stored,and retrieved by their position in the structure

3 An array is a structured data type made up of arraycomponents

By defintion; all the components of an array are the same datatype, the array is given a single name, array components are storedin adjacent memory locations.

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One dimensional arrays

Some additional common things

Arrays are created like: Type name[number ofcomponents];

int bp[1000];

The number of components is a constant integralexpression

The name of the array is also the base address of the array

An index in square brackets indicates the position of thecomponent in the arrayr = bp[13];

In general, the only aggregate operation defined for arrays isassignment (strings are slightly different)

An index that is out of range may cause strange things to happen:r = bp[-1];

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One dimensional arrays

Passing arrays to functions

Arrays are always passed by reference to a function.

The called function is responsible for staying within legalvalues for accessing array components.

There are two different ways to pass an array to a function:

By explicitly declaring an array is being passed:void Obtain(int [], int);

By declaring the address of the array being passed:void Obtain(int* , int);

Which one to choose depends on how the data is used by thefunction.

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Break time.

Take about 10 minutes.

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Practice exercises

Programs to load into CodeBlocks and get running:

1 cars.cpp working with structs

2 unions.cpp seeing how unions can work for and against you

3 addresses.cpp seeing how addresses can move you around

4 arrays.cpp playing with arrays (creating, assigning values,and printing values)

Others, if you have time.

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Q & A time.

Q: What do monsters eat?A: Things.Q: What do monsters drink?A: Coke. (Because Things gobetter with Coke.)

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What have we covered?

Finished Chapter 10 with unionsand addressesStarted Chapter 11 discussing onedimensional arrays (vectors)Looked at how to access arrayelements

Next time: continue Chapter 11

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References I

[1] Sylvia Sorkin, Programming and problem solving with c++,Teacher Resource Jones and Barlett Learning, 2014.

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Files of interest

1 unions.cpp Playing with unions

2 addresses.cpp Playing with

addresses

3 cars.cpp Reading and working with

structs

4 cars.dat Cars.cpp data file

5 arrays.cpp Creating arrays and

looking at addresses

unions.cpp#include

usingnamespacestd;

unionu_UnionType{

intanInt;

floataFloat;

doubleaDouble;

};

#defineWhereData(a)cout