itoa function trouble ??

This is a discussion on itoa function trouble ?? within the C Programming forums, part of the General Programming Boards category; Hi ! This is a program that i wrote to convert an integer to a string. however I came up ...

  1. #1
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    itoa function trouble ??

    Hi !

    This is a program that i wrote to convert an integer to a string. however I came up with a problem :

    The program does not work when I enter any negative number less than -999 and gives a wiered output

    Can anyone help me with this and tell me why ?

    I have placed ample comments in the program please let me know if still something is unclear.


    The code is :

    Code:
    #include<stdio.h>
    #include<string.h>
    
    void itoa(int n, char s[])
    {
         int i = 0;      /* variables to keep track of the index of the string */
         int j = 0;
         int k = 0;
         
         
         int sign = n;   /* variable to keep track of the sign of the integer */
         
         int temp;       /* temporary variable to store characters while reversing a string */
         
         /* make the number positive if it is negative */
         
         if (sign < 0)
            n = -n;
            
         /* run a loop and store each digit in the string ( in reverse order )*/
         
         do
         {
              s[i++] = n%10 + '0'; 
         }
         while((n/= 10) > 0);
         
         /* if the number was negative place a -ve sign at the end */
         
         if (sign < 0)
            s[i++] = '-';
         
         
         /* place a NULL character to mark the end of the string and bring the index marker i to the last character */
            
         s[i] = '\0';
         --i;
         
         /* loop to reverse the stirng */
         
        for( i = 0, j = (strlen(s) - 1); i < j; i++, j--)
         {
               temp = s[i];
               s[i] = s[j];
               s[j] = temp;
         }              
    }
    
    
    
    int main()
    {
        char s[] = "";
        int n = -1000;
        itoa(n, s);
        printf("%s\n", s);
        
        return 0;
    }

  2. #2
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    sorry to bother but I found my mistake

    in the above program i just posted I made a mistake


    " Please delete the iteration --i in line 66 "

    don't need that since in the for loop I start decrementing j from (strlen(s) - 1)

    sorry !!!!

  3. #3
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    Code:
     char s[] = "";
    You've still got a problem because you're not allocating enough memory for the 's' char variable. This will only allocate 1 byte for the '\0'

  4. #4
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    Code:
     char s[]
    is an unsized array.
    When no one helps you out. Call google();

  5. #5
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    > is an unsized array.
    No, it isn't.
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
    If at first you don't succeed, try writing your phone number on the exam paper.
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