call by value and call by reference

Call by Value      In  c  language by default  the arguments are passed to the function by value. It means  the actual arguments copy  their value into the formal arguments . In  call by value we can pass  the value  .if any change is  done into the formal arguments  it doesn't  affect the actual arguments because both  the arguments use the different memory location .

Program

#include<stdio.h>

#include <conio.h>

void  show ( int    a);

void main ()

{

Int x;

clrscr() ;

printf ( “enter the value “);

scanf(“%d”,& x);

show (x);

printf( “\n now value of x =%d” , x);

getch();

}

Void show ( int a )

{

a= a+1;

printf( “\n the value of a =%d”, a);

}

Call by reference   in this we can pass the address of a variable in place of value .this means we can pass the address of actual argument to the formal argument

#include<stdio.h>

#include <conio.h>

void  show ( int   * a);

void main ()

{

Int x;

clrscr() ;

printf ( “enter the value “);

scanf(“%d”,& x);

show ( &x);

printf( “\n now value of x =%d” , x);

getch();

}

void show ( int  *a )

{

*a=* a+1;

printf( “\n the value of a =%d”, *a);

}