Thread: Integer to String (itoa)

Hello cboarders!
I have written the below function, to convert integers to a character string.

The output correctly shows negative numbers. For positive numbers however, the string is not ending with a '\0'. I don't understand why it is not outputting with a '\0'.

1. Why is the '\0' not showing for positive numbers?
2. I have been asked to return "NULL" if the memory allocation fails. How do I know when the memory allocation has failed?

Thanks kindly for your help or guidance to get me on the right track!

Code:

char    *ft_itoa(int n)
{
    char    *str;
    int     digits;
    int     number;
    int     neg_flag;
    char    ip;


    digits = 0;
    neg_flag = 0;
    if (n < 0)
    {
        n = -1 * n;
        neg_flag = 1;
    }
    number = n;
    while(number > 0)
    {
        number = number/10;
        digits++;
    }
    if (neg_flag)
        digits = digits + 1;
    str = (char*)malloc(sizeof(char)*(digits + 1));
    str[digits + 1] = '\0';
    number = n;
    while (number)
    {
        ip = number % 10 + '0';
        str[digits - 1] = ip;
        digits--;
        number = number/10;
    }
    if (neg_flag)
        str[0] = '-';
    return (str);
}

MAIN:

Code:

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


int main () {
    int n;


    n = 20;
    printf("RESULT:\n%s",ft_itoa(n));


   return(0);
}

Ahh crystal clear now! thanks!!! Got confused with the digits and the positions in the string.. Thank you kindly