Recursion: base case returning 1, function returning 0

Hey,
I'm writing a recrusive function that is supposed to test a palindrome. I'm testing it out by inputing "racecar". My test statements indicate to me that the function should be returning 1(meaning it is a palindrome). However I'm getting returned 0. My understanding of recursion is a bit lacking right now I have a feeling I'm not fully understanding how a parent function handles the returned value. Could someone help me please?

Code:

---

#include <stdio.h>

int main()
{
  char string[ 15 ];
  scanf("%s", &string);

  printf("%d\n", testPalindrome(string, 6, 7) );

return 0;
}



int testPalindrome(char array[], int n, int size)
{
  if (size % 2 == 1 && (size - 1) / 2 == n ) {
      // TEST STATEMENT
      printf("if 1\n");
      return 1;
  }
  else if (size % 2 == 0 && (size - 1) / 2 == n) {
      // TEST STATEMENT
      printf("if 2\n");
      if (array[ n ] == array[ size - n ])
        return 1;
      else
        return 0;
  }
  else {
      // TEST STATEMENT
      printf("if 3\n");
      if (array[ n ] == array[ size - n - 1 ])
        testPalindrome(array, n - 1, size);
      else
        return 0;
  }

}

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where's your function declaration?

You may want to add a return to the call to testPalindrome() inside testPalindrom(). With that, it works on my machine. With warnings, the compiler says "not all paths have a return" (or some such) without the return, so you may want to enable warnings in the compiler.

--
Mats

thanks for the observation

i figured out i didn't specify what value to return. its working now

Quote:

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Originally Posted by matsp

You may want to add a return to the call to testPalindrome() inside testPalindrom(). With that, it works on my machine. With warnings, the compiler says "not all paths have a return" (or some such) without the return, so you may want to enable warnings in the compiler.

--
Mats

---

thank you

I simplified your code a bit.

Code:

---

#include <stdio.h>
#include <string.h>

int testPalindrome(char array[], int n, int size);

int main()
{
  char string[ 15 ];
  scanf("%s", string);

  printf("%d\n", testPalindrome(string, strlen(string)-1, strlen(string)) );

return 0;
}



int testPalindrome(char array[], int n, int size)
{
  if (size % 2 == 1 && (size - 1) / 2 == n ) {
      // TEST STATEMENT
      printf("if 1\n");
      return 1;
  }
  else {
      // TEST STATEMENT
      printf("if 3\n");
      if (array[ n ] == array[ size - n - 1 ])
        return testPalindrome(array, n - 1, size);
      else
        return 0;
  }

}

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