FUNCTION RECAP

WHAT IS FUNCTION?

A function is a section of a program that performs a specific task .

Solving a problem using different functions makes programming much simpler with fewer defects .

It’s a solution for a big project that split into small sub project.

Common Type (FUNCTION)

Void function Without argument Void unction With Input argument Function with input argument and single

result

Void function without argument syntax: void functionname(void)

Example:display()draw_circle()draw_triangle()

The nearest explantion is printf()

Void function without argument

void draw_triangle(void){

int row,space,star;

for(row=1;row<=9;row++)

{

for(space=8;space>=row;space--)

{

printf("%c",288);

};

for (star=1;star<row;star++)

{

printf("* "); }

printf("\n");

}

}

Why void? (most common seen in function without argument)

Void is use when the function does not return any value

More explanation:

The subfunction is called draw_triangle()from the main function but the function

prototype is written as void draw_triangle(void)

Void function with input argument

syntax: functiontype functionname(input)

Example:double box(123.45)circumference(5.0)calculate(inum1)

Void function with input argument

void box(double num){

printf("***********\n");printf("* *\n");printf("* *\n");printf("* %7.2f *\n",num);printf("* *\n");printf("* *\n");printf("***********");}

#include<stdio.h>#include<conio.h>

void box(double num){printf("***********\n");printf("* *\n");printf("* *\n");printf("* %7.2f *\n",num);printf("* *\n");printf("* *\n");printf("***********");}

int main(){ box(123.45);getch();return 0; }

VOID>> and what is the different between both function shown

void box(double num)

void draw_triangle(void)

Function with input argument and single result

syntax: functiontype

functinname(input argument)

Example:double circumferencecal(int rads);

Function with input argument and single result#include<stdio.h>

#include<conio.h>

double circumferencecal(int rads);

int main(){

int rads=5; double circum;

circum=circumferencecal(rads);

printf("Ukur lilit bagi bulatan bagi ber-radius-kan %d adalah %.4lf",rads,circum);

getch();

return 0;

}

double circumferencecal(int rads){

double x;

float pi=3.1415;

x=2*pi*rads;

return(x);

}

Returning values• The result of the function can be given back to the calling

functions

• Return statement is used to return a value to the calling function

• Syntax:

return (expression) ;

• Example:

return(iNumber * iNumber);

return 0;

return (3);

return;

return (10 * i);

Function with multiple arguments

Syntax:

functionname(argument1,argument2)

Example:circumferencecal(radian,PI);

#include<stdio.h>

#include<conio.h>

double circumferencecal(int rads,double PI);

int main(){

int rads=5; double circum,PI=3.1415;

circum=circumferencecal(rads,PI);

printf("Ukur lilit bagi bulatan bagi ber-radius-kan %d adalah %.4lf",rads,circum);

getch();

return 0;

}

double circumferencecal(int rads,double PI){

double x;

x=2*PI*rads;

return(x);

}

Chotto complicated example#include<stdio.h>

#include<conio.h>

#include<math.h>

double circumferencecal(int rads,double PI){

double x;

x=2*PI*rads;

return(x);

}

double areacal(int rads,double PI){

double y;

y=PI*pow(rads,2);

return(y);

}

int main(){

int rads=5; double area,circum,PI=3.1415;

circum=circumferencecal(rads,PI);

area=areacal(rads,PI);

printf("Ukur lilit bagi bulatan bagi ber-radius-kan %d adalah: %.4lf\nManakala luasnya pula: %.4lf",rads,circum,area);

getch();

return 0;

}

Do and Don’t in Function

DODo use local variable whenever possible

Do limit each function to a single task

DON’TDon’t try return a value that has a type different from the function’s type

Don’t let functions get too long. If a function starts getting long, try to break it into separate smaller tasks.

Don’t have multiple return statements if they aren’t needed. You should try to have one returns when possible; however, sometimes having multiple return statement is easier and clearer.

GOTO

GO TO

Is a function in programming c that allows you to jump according to designation labels

Syntax:goto label;Just simply means to redirect you to the label located in the coding

label: Just simply means to redirect you to the label

Example