CODEWITHSUNDEEP
cfunctionrecursion
prashad
prashad

Reputation: 107

recursive function behaviour

program 1:

unable to print nothing, even we passed string s.

void reverse(char *s)
{
    if(*s)
    {
        return reverse(s+1); 
        printf("%c",*s);
    }
}

program 2:

works as exact behaviour, it printing the string in reverse order.

void reverse(char *str)
{
    if(*str)
    {
        reverse(str+1);
        printf("%c", *str);
    }
}

could anybody know ,what would be the problem for program 1.
I think, in recursive function, we should put return statement before the function. is it must to put the return statement/necessary??.

Upvotes: 1

Views: 130

Answers (2)

Lundin
Lundin

Reputation: 213533

This has nothing to do with recursion. The printf statement is dead code and won't work for the same reason as

int main()
{
  return 0;
  printf("hello, world");
}

doesn't work. You should get compiler warnings for such code.

Furthermore, your recursive function needs a condition where it stops calling itself, or it will just endlessly spawn new functions until you get a stack overflow.

Upvotes: 2

Vlad from Moscow
Vlad from Moscow

Reputation: 310940

In the first program there is return statement that exits the function without printing anything. That is the function calls itself recursively and in each recursion it returns control at once to the caller. The comtrol never achieves the print statement.

In fact the function can be rewritten like

void reverse(char *s)
{
    if(*s)
    {
        return reverse(s+1); 
    }
}

Upvotes: 0

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