output generated even though there's no return in function ?

Code:

---

#include<stdio.h>
int power(int,int);
main()
{
        int x,y,o=1;
        while(o==1)
        {
        printf("\nEnter the 2 desired numbers : ");
        scanf("%d%d",&x,&y);
        printf("\nThe answer is %d.\n",power(x,y));
        printf("\nWant another one ?\n1.Yes\n2.No\n");
        scanf("%d",&o);
        }
}
int power(int a,int b)
{
        int i,res=1;
        for(i=1;i<=b;i++)
        {
                res=res*a;
        }
}

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I haven't given any return for power function. But I'm getting an output of y+1 !!!

Why is this happening ?

Yes, it's actually a feature. :D
I wrote my rand() function using this feature.

Code:

---

int rand() {
// no return !
}

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but the output is fixed...I'm getting the 2nd number +1 as the output...why ?

"Why" is because you declared it as returning int.

So you get whatever junk value happens to be in the return location in the code generated by the compiler.
Most of the time, this looks something like the result of the last arithmetic operation in the code.

In any event, use a better compiler and write better code.

Code:

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$ gcc -Wall bar.c
bar.c:4: warning: return type defaults to ‘int’
bar.c: In function ‘power’:
bar.c:22: warning: control reaches end of non-void function
bar.c: In function ‘main’:
bar.c:14: warning: control reaches end of non-void function

---

Quote:

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Originally Posted by Salem

"Why" is because you declared it as returning int.

So you get whatever junk value happens to be in the return location in the code generated by the compiler.
Most of the time, this looks something like the result of the last arithmetic operation in the code.

---

which is the value of i, the last computation before the termination of the loop.

Quote:

---

In any event, use a better compiler and write better code.

---

Nothing is necessarily wrong w/ his compiler, just had to compile with warning option/strict mode etc. like you did

Do you equate "0 warnings 0 errors" with being "bug free" ?

Even when you know "the answer", it isn't information you can use in any other program / OS / Compiler combination.

It's like arguing over what is x++ + x++ or fflush(stdin), the answer is deep in undefined behaviour. So spending time analysing a specific case is a complete waste of effort, because you won't be able to use what you know in any other program.

couldn't agree more.
just explained where the return value comes from, and yeah, it is an undefined behaviour.