MELJUN CORTES C++ chapter 1 c++ fundamentals

C FundamentalsC Fundamentals

MELJUN CORTESMELJUN CORTEScomputer program user

Word

excel

photoshop

C Programming C Programming LanguageLanguage

MELJUN CORTES, MELJUN CORTES, MBA,MPA,BSCSMBA,MPA,BSCS

School of Computer InformationSchool of Computer Information 2

IntroductionIntroduction

We will learnWe will learn The C programming languageThe C programming language Structured programming and proper programming techniquesStructured programming and proper programming techniques

This book also coversThis book also covers C FundamentalsC Fundamentals Control StatementsControl Statements Data types, variables and ExpressionsData types, variables and Expressions Arrays and StringArrays and String

This course is appropriate forThis course is appropriate for Technically oriented people with little or no programming Technically oriented people with little or no programming

experience experience Experienced programmers who want a deep and rigorous Experienced programmers who want a deep and rigorous

treatment of the languagetreatment of the language


ProgramProgram

Computer = hardware + softwareComputer = hardware + softwareProgram makes computer to general purposeProgram makes computer to general purpose


computer program user

Word

excel

photoshop


What is computer?What is computer?

Computer processing data by instruction.Computer processing data by instruction.



Smart PhoneSmart Phone

Smart phone is a kind of computerSmart phone is a kind of computer



History of computerHistory of computer

Eniac : vacuum tubeEniac : vacuum tube



Von Neumann Architecture

Store data and program in Main memoryStore data and program in Main memory


data

program

Main memory

CPU

Von Neumann


Machine LanguageMachine Language

Machine LanguageMachine Language


http://www.google.co.kr/url?sa=i&rct=j&q=machine+language&source=images&cd=&cad=rja&docid=ySXmv9CIlABqEM&tbnid=X7cN2uPsxYJ1AM:&ved=0CAUQjRw&url=http://www.uigarden.net/english/the-application-of-model-matching-principle-in-user-interface-design-part-2&ei=nRAjUcKHOui0igLSh4HIBQ&bvm=bv.42661473,d.cGE&psig=AFQjCNHO6MKdocFOCt36g-MzuNTo3rpF7w&ust=1361338899519882


CompilerCompiler

We need compilerWe need compiler


ProgrammingLanguage

MachineLanguage

Compiler

01000110101010100101010101010110010

111111

if( x > 0 ) pos++;else neg++;

English Korean

Translator

시작이 좋으면 끝도 좋다 ....

A good beginning makes a good ending....



History of CHistory of C

C C Evolved by Ritchie from two previous programming languages, Evolved by Ritchie from two previous programming languages,

BCPL and BBCPL and B Used to develop UNIXUsed to develop UNIX Used to write modern operating systemsUsed to write modern operating systems Hardware independent (portable)Hardware independent (portable) By late 1970's C had evolved to "Traditional C"By late 1970's C had evolved to "Traditional C"

StandardizationStandardization Many slight variations of C existed, and were incompatibleMany slight variations of C existed, and were incompatible Committee formed to create a "unambiguous, machine-Committee formed to create a "unambiguous, machine-

independent" definitionindependent" definition Standard created in 1989, updated in 1999Standard created in 1989, updated in 1999


Father of C languageFather of C language

Dennis Ritchie awarded National Medal of Dennis Ritchie awarded National Medal of TechnologyTechnology




Feature of CFeature of C

System programming available as Low level type high level System programming available as Low level type high level language language ➡ middle level language➡ middle level language Low level language : handle to real instructions for computerLow level language : handle to real instructions for computer’’s execution s execution

(machine language of assembly type)(machine language of assembly type)Ex) Assembly languageEx) Assembly language

High level language : support of several control structures and I/O High level language : support of several control structures and I/O instruction (facilitate programming)instruction (facilitate programming)

Ex) Pascal, Delphi, VB, JavaEx) Pascal, Delphi, VB, Java

C programs consist of pieces/modules called functionsC programs consist of pieces/modules called functions Suit structural programmingSuit structural programming

Sequence/Conditional/Repetable structureSequence/Conditional/Repetable structure

Various data structure, operation and function libraryVarious data structure, operation and function library Higher portability to other systemsHigher portability to other systems



The C Standard LibraryThe C Standard Library

C programs consist of pieces/modules called functionsC programs consist of pieces/modules called functions A programmer can create his own functionsA programmer can create his own functions

Advantage: the programmer knows exactly how it worksAdvantage: the programmer knows exactly how it works Disadvantage: time consumingDisadvantage: time consuming

Programmers will often use the C library functionsProgrammers will often use the C library functions Use these as building blocksUse these as building blocks

Avoid re-inventing the wheelAvoid re-inventing the wheel If a premade function exists, generally best to use it rather than If a premade function exists, generally best to use it rather than

write your ownwrite your own Library functions carefully written, efficient, and portableLibrary functions carefully written, efficient, and portable



Basics of a Typical C Program Basics of a Typical C Program Development EnvironmentDevelopment Environment

• Phases of C Programs:

1. Edit

2. Preprocess

3. Compile

4. Link

5. Load

6. Execute

Program is created inthe editor and storedon disk.

Preprocessor programprocesses the code.

Loader puts program in memory.

CPU takes eachinstruction and executes it, possibly storing new data values as the program executes.

Compiler creates object code and storesit on disk.

Linker links the objectcode with the libraries

Loader

Primary Memory

Compiler

Editor

Preprocessor

Linker

Primary Memory

.

.

.

.

.

.

.

.

.

.

.

.

Disk

Disk

Disk

CPU

Disk

Disk


First ProgramFirst Program

Run Microsoft Visual C++Run Microsoft Visual C++




Select File and NewSelect File and New




Win32 Console ApplicationWin32 Console Application




Empty projectEmpty projectFinishFinishOKOK




Empty projectEmpty project




File-New-C++source FileFile-New-C++source File Input file nameInput file name




Input this codeInput this code


01 # include <stdio.h>0203 int main()04 {05 printf(“%d”, 100-50);06 }



Build-Build first.exeBuild-Build first.exe




If an error : missing semicolonIf an error : missing semicolon




Build-Execute First.exeBuild-Execute First.exe




1.1. Understand the components Understand the components of a C programof a C program

All C programs consist of one or more functionsAll C programs consist of one or more functions Each function contains one or more statementsEach function contains one or more statements The general form of a C FunctionThe general form of a C Function

ret-typeret-type function-name() function-name() ➡ name of the function➡ name of the function

{{ ➡ start of the function➡ start of the function

statement sequencestatement sequence ➡ statements of the function➡ statements of the function

}} ➡ end of the function➡ end of the function




Function nameFunction name upper- and lowercase letters of alphabetupper- and lowercase letters of alphabet( A~Z, a~z )( A~Z, a~z ) digitsdigits( 0~9 ) ( 0~9 ) cannot start a function name cannot start a function name underscoreunderscore( _ )( _ ) Case-sensitive Case-sensitive ex) Myfun ex) Myfun ≠≠ myfun myfun

A C program may contain several functionsA C program may contain several functions Must have a main()Must have a main() The main( ) is where execution of your program beginsThe main( ) is where execution of your program begins The main( ) is when your program begins runningThe main( ) is when your program begins running Executing statements are included inside Executing statements are included inside ‘‘{{’’ and and ‘‘}}’’ All C statements end with a semicolonAll C statements end with a semicolon(;)(;) You may place two or more statements on one lineYou may place two or more statements on one line



C program StructureC program Structure




Example of C program StructureExample of C program Structure





ANSIANSI C standard specifies a set of library functions to be supplied C standard specifies a set of library functions to be supplied by all C compilers, which your program may useby all C compilers, which your program may use

C standard libraryC standard library I/O (input/output) functionI/O (input/output) function String manipulation functionString manipulation function Mathematical compugation functionMathematical compugation function Etc.Etc.

header fileheader file File extension : File extension : .h .h #include#include preprocessor directivepreprocessor directive

C ignores spaces C ignores spaces






2. Create and compile a program2. Create and compile a program

Turbo C++Turbo C++ Program-development environmentsProgram-development environments Development stepsDevelopment steps



2. Create and compile a program2. Create and compile a program

A direction of compile processingA direction of compile processing



3. Declare variables and 3. Declare variables and assign valuesassign values

VariableVariable A named memory locationA named memory location Can hold various valuesCan hold various values




Variable declarationVariable declaration Form : Form : type var-nametype var-name

type : C data type type : C data type var-name : name of the variablevar-name : name of the variable

Declaration places of variable Declaration places of variable Global variable : outside all functionsGlobal variable : outside all functions Local variable : inside a functionLocal variable : inside a function

The same type variables declarationThe same type variables declaration

int count ;int count ;

float x;float y;float z;

float x;float y;float z;

float x, y, z ;float x, y, z ;




Assignment operationAssignment operation Form : Form : vaiable-name = value;vaiable-name = value;

Ex) num = 100;Ex) num = 100;

ConstantConstant Fixed valueFixed valueEx) Ex) ‘‘AA’’, , ‘‘aa’’, 100, 100.0, 100, 100.0

Display of characters, integers and floating-point valuesDisplay of characters, integers and floating-point values

Format specifiers of printf()Format specifiers of printf() %d%d(decimal format)(decimal format), %c, %c(character value)(character value), %f, %f(float, double)(float, double)

printf(“This prints the number %d”, 99);printf(“This prints the number %d”, 99);




Example 1.Example 1. Example 2.Example 2.



4. Input numbers from the keyboard4. Input numbers from the keyboard

Standard input/outputStandard input/output




scanf()scanf() Standard function for input numbers from the keyboardStandard function for input numbers from the keyboard Format : Format : scanf( scanf(““%d%d””, &int-var-name);, &int-var-name);

Ex) int num;Ex) int num; scanf(scanf(““%d%d””, &num);, &num);

Format : Format : scanf( scanf(““%f%f””, &float-var-name);, &float-var-name);




Input number from the keyboardInput number from the keyboard







ExerciseExercise Write a program that inputs two floating-point Write a program that inputs two floating-point

numbers numbers (use type float)(use type float) and then displays their sum. and then displays their sum.

*** Addition program ***

First num : 15

Second num : 20

15 + 20 = 35

*** Addition program ***

First num : 15

Second num : 20

15 + 20 = 35



5. Perform calculations using arithmetic 5. Perform calculations using arithmetic expressionsexpressions

Arithmetic operatorsArithmetic operators + : addition+ : addition - : subtraction- : subtraction * : multiplication* : multiplication / : division/ : division % : modulus% : modulus

ex)ex)




Exercise #1Exercise #1 Write a program that computes the volume of a cube. Have the Write a program that computes the volume of a cube. Have the

program prompt the user for each dimension.program prompt the user for each dimension.

Input width : 15Input length : 10Input height : 12The volume of a cube : 1800

Input width : 15Input length : 10Input height : 12The volume of a cube : 1800




Exercise #2Exercise #2 Write a program that computes the number of Write a program that computes the number of

seconds in a year.seconds in a year.

The seconds of a year : 31536000 sec The seconds of a year : 31536000 sec



6. Add comments to a program6. Add comments to a program

CommentsComments A note to yourself that you put into your source code.A note to yourself that you put into your source code. All comments are ignored by the compiler.All comments are ignored by the compiler.

/* This is a comment. */ /* This is a comment. */ /* /* This is a long comment.This is a long comment. Me too! Me too! */*/

int i ;int i ; //this is daclaration of variable//this is daclaration of variable

/* comment start*/ comment end// only this line after it

/* comment start*/ comment end// only this line after it




nested comments problemnested comments problem




ExampleExample A year on Jupiter A year on Jupiter (the time takes for Jupiter to make one full (the time takes for Jupiter to make one full

circuit around the Sun) circuit around the Sun) takes about 12 Earth years. The takes about 12 Earth years. The following program allows you to convert Earth days to Jovian following program allows you to convert Earth days to Jovian years.years.

Simply specify the number of Earth days, and it computes the Simply specify the number of Earth days, and it computes the equivalent number of Jovian years. Notice the use of comments equivalent number of Jovian years. Notice the use of comments throughout the program.throughout the program.



7. Write your own functions7. Write your own functions

Functions are the building blocks of C.Functions are the building blocks of C.




Most real-world programs will contain many functions.Most real-world programs will contain many functions. ret-typeret-type specifies the type of data returned by the function. specifies the type of data returned by the function.

void : function does not return a valuevoid : function does not return a value A function prototypeA function prototype declares a function before it is used and prior to declares a function before it is used and prior to

its definition.its definition. FunctionFunction’’s names name Return typeReturn type Parameter listParameter list

The compiler needs to know this information in order for it to properly execute a call to the function.

The compiler needs to know this information in order for it to properly execute a call to the function.




Example 1Example 1




Execution order of Example 1Execution order of Example 1




Example 2Example 2



8. Use functions to return values8. Use functions to return values

A function may return a value to the calling routine.A function may return a value to the calling routine.

#include <stdio.h> #include <math.h> /* needed by sqrt() */ int main(void) { double answer;

answer = sqrt(10.0); // sqrt() call assign to answer printf ("%f", answer);

return 0; }

#include <stdio.h> #include <math.h> /* needed by sqrt() */ int main(void) { double answer;

answer = sqrt(10.0); // sqrt() call assign to answer printf ("%f", answer);

return 0; }




In functions, you can return a value to the calling routine using the In functions, you can return a value to the calling routine using the returnreturn statement. statement.

• form : return value ;

(constant or variable or expression)

int func(void) { return 10; /* return 10 to calling routine. */ }

int func(void) { return 10; /* return 10 to calling routine. */ }

int func(void) ; int main(void) { int num;

num = func(); /* func() call receive a value(10). */ printf(“%d”, num);

return 0; }

int func(void) ; int main(void) { int num;

num = func(); /* func() call receive a value(10). */ printf(“%d”, num);

return 0; }




Example 1Example 1




Example 2Example 2




ExerciseExercise Write a program that uses a function called convert(), which Write a program that uses a function called convert(), which

prompts the user for an amount in dollars and returns this value prompts the user for an amount in dollars and returns this value converted into pounds. converted into pounds. (Use an exchange rate of $2.00 per (Use an exchange rate of $2.00 per pound.)pound.) Display the conversion. Display the conversion.

Input dollars : 1515.00 dollars are 7.50 pounds.

Input dollars : 1515.00 dollars are 7.50 pounds.



9. Use function arguments9. Use function arguments

A A functionfunction’’s argumentss arguments is a value that is passed to the is a value that is passed to the function when the function is called.function when the function is called.

The The formal parameterformal parameter is special variables to receive is special variables to receive argument values.argument values.

void sum(int x, int y) {

printf(“%d ”, x + y);

}

void sum(int x, int y) {

printf(“%d ”, x + y);

}




#include <stdio.h> int sum(int x, int y);

int main(void) { sum(1, 20); /* 1 and 20 are arguments to function */ sum(9, 6); sum(81, 9);

return 0; }

int sum(int x, int y) { /* x and y are parameters of function */ printf ("%d\n ", x + y); return 0; }

#include <stdio.h> int sum(int x, int y);

int main(void) { sum(1, 20); /* 1 and 20 are arguments to function */ sum(9, 6); sum(81, 9);

return 0; }

int sum(int x, int y) { /* x and y are parameters of function */ printf ("%d\n ", x + y); return 0; }




Example 1Example 1

Example 2Example 2 This program uses the out char() function to output characters to the This program uses the out char() function to output characters to the

screen.screen.

sum(10-2, 9*7);sum(10-2, 9*7); sum(8, 63);sum(8, 63);




ExcercisesExcercises Write program that uses a function called Write program that uses a function called outnum()outnum()

that takes one integer argument and displays it on the that takes one integer argument and displays it on the screen.screen.

Input integer number : 43Your input number is 43

Input integer number : 43Your input number is 43



10. Remember the C keywords10. Remember the C keywords

autobreakcasecharconstcontinuedefaultdo

doubleelseenumexternfloatforgotoif

intlongregisterreturnshortsignedsizeofstatic

structswitchtypedefunionunsignedvoidvolatilewhile

asm_ssinterrupt

_cscdeclnear

_dsfarpascal

_eshuge

KeywordsKeywords

Extended KeywordsExtended Keywords