34. Pointer and Functions

Passing addresses to Functions:

Look at this porgram

#include<stdio.h>

void arnob(int,int)

main( )

{

int a=10,b=20;

arnob(&a,&b);

printf("\na=%d",a);

printf("\nb=%d",b);

}

arnob(int *x,int *y)

{

int t;

t=*x;

*x=*y;

*y=t;

}

The output of the above program would be:

a=20

b=10

  When we send the address of  a and b it come in the function arnob. But we know that the normal variable can not store the address of a variable. So if we want to store the address of a and b we mast declere the pointer type variable. Because we know that only pointer type variable can store the address of a variable. So in the function arnob we declear two pointer x and y to store the address of a and b. And we also declear a normal variable t. Now we put the value of *x in t. Also we know that *x mean 'value at address x' that means  a. And we know a=10. So t=*x mean that t=a i mean t=10. Now *x=*y mean that a=b. So tha valu of a is now 20. *y=t, we know that the valu of t=10. So *y=t mean b=10. Look at this porgram we work in tha fanction arnob. But the value of a and b change in the main function.

post by Arnob