[SOLVED] clarification of recursive "function return"

atlantis43 · 05-12-2015, 11:12 AM

The following statement (and included code example) is from a textbook discussion of recursive functions, and I am unclear as to the meaning of "return". Is there an implied

Code:

return;

in all void functions that is part of the C Standard?

Quote:

"When program flow reaches the return at the end of the last recursion level, control passes to the previous recursion level."

Code:

#include <stdio.h>
void up_and_down(int);

int main(void)
{
    up_and_down(1);
    return 0;
}

void up_and_down(int n)
{
    printf("Level %d: n location %p\n", n, &n); // 1
    if (n < 4)
        up_and_down(n+1);
    printf("LEVEL %d: n location %p\n", n, &n); // 2
    
}

johnsfine · 05-12-2015, 11:14 AM

Yes. There is an implied return where code reaches the end of any function.

If it is a void function, the compiler can reasonably assume the implied return was the intent of the programmer.

If it is a function that should return a value, the standard does not specify what value the implied return returns. So the compiler should give at least a warning, if not an error.

You have an explicit return in the function that returns int and your implied return is in a void function, so no problem.