Cannot find my error

Hi there, I am trying to create a function that takes in any integer and convert it into a string. For example 1000 ---> "1000".

I have gone through an hour trying to figure out my error, but I just can't find it, so I've decided to seek help...here's my code:

Code:

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




char intToCh(int i) {
        char char_result;
        char character_array[36] =                {'0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P','Q','R','S','T','U','V','W','X','Y','Z'};




        char_result = character_array[i];




        return char_result;
        }




char* string_of_int;


char* intToString(int integer) {
       
        int len_of_int = log10(integer) + 1;
        int expon = log10(integer);
        int divider;
       


        int i = 0;


                for(i = 0; i < len_of_int; i++) {
                        int temp;


                        if (integer == 0) {
                                break;
                        } else {
                        divider = pow(10, expon);
                        temp = integer / divider;
                        string_of_int[i] = intToCh(temp);
                       
                        }
                        integer = integer - (temp * divider);
                        expon--;
                }
       
        return string_of_int;
}










int main(void) {


intToString(1000);






printf("%s\n", string_of_int);








return 0;


}

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The compile errors:

Code:

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/tmp/cctRlDcq.o: In function `intToString':IntToString.c:(.text+0xe3): undefined reference to `log10'
IntToString.c:(.text+0x100): undefined reference to `log10'
IntToString.c:(.text+0x137): undefined reference to `pow'
collect2: ld returned 1 exit status

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I am really confused by the undefined reference because I have already included the math.h library, but it seems like it's not recognized.


Thank you,


-Genxi

"undefined reference to" normally means a linking error; try linking to the needed library.
I would guess the math library; this library is often called just by the letter m.

Edit: You say you already linked to math.
You might try casting the types to double; IIRC some old compilers required that the signature match.

Edit2: Nearly all linkers require the library/object files to be in the correct order; the order changes for compiler brands.

Tim S.

Hey Tim,

I've tried compiling with the following:

Code:

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gcc -Wall -o IntToString IntToString.c -lm

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but, after I ran the code, it gave me the segmentation fault.

Any more ideas?


-Genxi

Allocate space for what string_of_int points to.

Tim S.

Thank you for your advices, Tim! I got my code to work after allocating some space and linking by -lm. -high five-!!!

Hmmm ... just use snprintf() if you have a C99 compiler, sprintf() otherwise.

Code:

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snprintf(string_of_int, <WHATEVER_SIZE_YOU_ALLOCATED>, "%d", 1000);

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