Different Output

[ashlee]

I write the following C program and a ran the program

#include <stdio.h>
int * test(int, int);
void main()
{
int *ex = test(10,20);
printf("\nSample Testing\n");
printf("%d",*ex);
}
int *test(int a,int b)
{
int c = a + b;
return &c;
}

In the above program I thought the output would be
Sample Testing
30

But I got output as
Sample Testing
some junk value

Why is it so? I am confused on the output the system shows. Someone highlight me your knowledge on this.

[Adrian]

It is because the function test(10,20) is passed by value and you have calculated c = a + b which is fine. But you have returned the address of c which is collected in a pointer. It is possible to change the address value and so you have got a junk value. For retrieving the value you can even pass by reference and get the return value in the function name itself.