Chapter3 c Fundamentals

Chapter 3C FUNDAMENTALS

Electrical Engineering Department

Faculty of Information Technology and Multimedia, 2008/2009

Learning Objectives:

◊ Understand and implement the basic structure of computer programming.

EC201 Fundamental Programming


Involves translating high-level language (programminglanguage such as C,C++, Java, PHP,Visual Basic, C#,etc.)

WHY? Because computers do NOT understand high level language!

Translated to

000111010101010111011111 EC201 Fundamental Programming

Program Development Environment


Typical program development environment consist of six phases to be executed.

Edit

Preprocess

Compile

Link

Load

Execute EC201 Fundamental Programming



Creating a ProgramPhase 1: Programmer types or creates program in an editor. Makes corrections if necessary. Saves or stores program on disk such as C:\ or A:\ etc. Editor

?Editor or text editor is a type of program used for editing plain text files.




Turbo C

editor(free)




Miracle C

editor(free)




PreprocessingPhase 2:

Programmer gives command to compile the program. Preprocessor program executes automatically and process

the program code. The prepocessor obeys commands from preprocessor

directives. Preprocessing occurs before a program is compiled.




Compiling a ProgramPhase 3: When compiled, compiler translates program into machine language code and creates object code. The object code will be stored in disk.

Dialog box in Turbo C

editor shows

compiling process.

Programmer click

Compile




Compiling a ProgramPhase 3:

The object code will be only created if the translation process into machine code is successful.

Otherwise, if unsuccessful, error messages will be displayedin the compiling dialogue box.

Programmer must fix all the errors before proceed to the next phase.

The process of correcting errors is called debugging.




LinkingPhase 4:

A linker links the object code with the libraries. A linker will creates an executable file and stores it on disk

if the program compiles and links correctly. A linker might name the executable file with .exe file

extension depending on type of programming languageused.




LoadingPhase 5:

Before a program can be executed, the program must firstbe placed in memory.

Loader takes the stored program from disk and puts in memory.

Additional components from shared libraries that support the program are also loaded.




ExecutingPhase 6:

CPU takes each instructions and executes it. Results or output will be displayed.




Terms DescriptionMachine language Binary number codes understood by a

specific CPU.High-level language

Machine-independent programming language that combines algebraic expressions and English symbols.

Source file File containing a program written in a high-level language; the input for compiler

Compiler Software that translates a high-level language program into machine language.

Linker Software that combines object files and create an executable machine language program. EC201 Fundamental Programming



Computer Program

HOW WHAT

UNDERSTAND THE SYNTAX AND

FORMAT STRUCTURE OF PROGRAMMING




C Basic Structure

C preprocessor directive

main function{ //Identifiers/Variables //C statements}

Program block components:

1. Preprocessor directive

2. Program body3. Main function4. Identifiers/

Variable5. C statements6. Comment


Basic Syntax of Programming


PROGRAMBLOCK

PREPROCESSOR

DIRECTIVEMAIN

FUNCTIONIDENTIFIERS/

VARIABLE

C STATEMENT

COMMENT

PROGRAMBODY

PICK AND MATCH



Preprocessor Directive

Utility program which link files from compiler library to the program code. Must be included in the first line of a computer program. Must be started with the symbol #, otherwise syntax errors

will be occurred. Two types of common preprocessor directive: #include and

#define.





#include <header file> or #include “user defined files”

Format:

Example#include <stdio.h>#include <conio.h>#include “jam.h”




Preprocessor DirectiveExample:

#include <stdio.h>

A directive to the C preprocessor Lines beginning with # are processed by the

preprocessorbefore the program is compiled.

The above code line tells the preprocessor to include thecontents of stdio.h ( standard input/output header)

Called from standard library




Standard Library

Consists of built-in functions

Functions contains standard instructions

Function will be called and linked to program via header file

List of header file and its functionFunction Header FileStandard input/output functions

<stdio.h>

Mathematical functions <math.h><stdlib.h><time.h>

String functions <string.h> <ctype.h>




Standard Library

List of header file and its functionHeader file List of functions

stdio.h printf(), scanf(),fflush(), dll

conio.h clrscr(),putch().getc().dll

math.h sqrt(),pow(), log(),dll




STANDARD INPUT/OUTPUT FUNCTIONS <stdio.h>

stdio.h

getchar()

gets()

scanf()

putchar()

puts()

printf()

INPUT

OUTPUT



STANDARD INPUT/OUTPUT FUNCTIONS (cont.)

Function Descriptionprintf() Prints all types of data to the screenputs() Prints string to the screen including newline

(‘\n’)int putchar(int c) Prints a character to the screenscanf() Inputs all type of data from user (up to a

spacing)gets() Inputs string from user (up to enter key). int getchar(void) Inputs a character from userfflush(stdin) During getting inputs from user, there might

be an extra character (such as ‘\n’) still exists in buffer from the previous input. If

the buffer is not empty, the next input reads the extra character and not the input from

user. Write fflush(stdin) to empty the input buffer before the next character input.

OU

TPU

TIN

TPU

T


STANDARD INPUT/OUTPUT FUNCTIONS <stdio.h>


MATHEMATICAL FUNCTIONS

math.h

stdlib.h

Mathematical

Functions

Mathematical

Functions

Mathematical

Functions

math.h

Mathematical

Functionsstdlib.h

math.h

Mathematical

Functions



MATHEMATICAL FUNCTIONS <math.h>

Function Descriptiontan (x) Tangent of x

(x in radians)sin (x) Sine of x

(x in radians)cos (x) Cosine of x

(x in radians)sqrt (x) Square root of x pow (x, y) x raised to power of y

(xy)abs (a) Absolute value of a

(for integer type only)fabs (x) Absolute value of x

(for floating type only)log (x) Natural algorithm of x (base e).

Returns ln x. (error occurs if x ≤ 0)

log10 (x) Logarithm of x (base 10) (error occurs if x ≤ 0)

MATHEMATICAL FUNCTIONS



STRING FUNCTIONS

string.h

ctype.h

StringFunctions



STRING FUNCTIONS <string.h>

Function Descriptionstrcat(s1,s2) Combines/concatenates string s2 to string s1.

strcpy(s1,s2) Copies string s2 into string s1.

strcmp(s1,s2) Compares the string s1 with the string s2.

If s1 is equal to s2, returns 0.If s1 is greater than s2, returns positive value.If s1 is less than s2, returns negative value.

strlen(str) Returns the length/size of str.

STRING FUNCTIONS <string.h>



STRING FUNCTIONS <ctype.h>

Function Descriptionisdigit(c) Returns a nonzero (true) if c is a digit (0-9), otherwise zero (false).

isalpha(c) Returns a nonzero (true) if c is a letter (A-Z, a-z), otherwise zero (false).

isupper(c) Returns a nonzero (true) if c is an uppercase letter (A-Z), otherwise zero (false).

islower(c) Returns a nonzero (true) if c is a lowercase letter (a-z), otherwise zero (false).

isspace(c) Returns a nonzero (true) if c is a whitespace character such as newline (‘\n’), space (‘ ’), or horizontal tab (‘\t’), otherwise zero (false).

toupper(c) If c is a lowercase letter, toupper() returns c as an uppercase letter. Otherwise, toupper() returns the same value unchanged.

tolower(c) If c is an uppercase letter, tolower() returns c as a lowercase letter. Otherwise, tolower() returns the same value unchanged.



User-definedLibrary

List of header file and its function

Contain functions defined by programmer.

Developed by expert programmers.

Header file List of user-defined functions

utama.h cetak(),baca(),papar(),dllkira.h plus(),minus(), divide(),dll





#define “file name” or #define constant_name constant_value

Format:

Example#define MAX 100#define “jam.h”




Program Body The part in which the program code will be started to

execute. Consists of main function, C statements and identifiers. Use { to start the program code and } to end the

program code.

main function { //identifiers //C statements }

Format:




Main function

int main( ){ return 0;} Main function

void main( ){ …………..}

main( ){ return 0;}



Faculty of Information Technology and Multimedia, 2008/2009Principles of Programming - NI 2005

34

Function main• Identify the start of the program• Every C program has a main ( )• 'main' is a C keyword. We must not use it

for any other variable.• 4 common ways of main declaration

int main(void)

{

return 0;}

void main(void)

{

}

main(void)

{

}

main( )

{

}


The curly braces { }


•Identify a segment / body of a programThe start and end of a functionThe start and end of the selection or repetition block.

•Since the opening brace indicates the start of a segment with the closing brace indicating the end of a segment, there must be just as many opening braces as closing braces (this is a common mistake of beginners)


Write the most basic structures of C programming.

#include <stdio.h>void main(){}




C StatementInstructions to be executed by computersEvery statements must be ended with semicolon

Types

Declarationstatement

Input/Output statement

Control statement

Functionstatement




CommentStatement in program code that will be ignored by compilerDiffers in terms of colour : grey or greenFormat use ; /*……………………….*/

//……………………………

Function

To documenta program

As a future

references

To provide additional

information

To increaseprogram

readability



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Chapter3 c Fundamentals