Question

This code is driving me up the wall. The goal is to split to char[] based on a comma. It works in java. But prints weird output in C. The error I suspect is at 28 on the second iteration of the loop where I tried to add 5 the array turns into weird characters.

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

main()
{
    char asshat[] = {'4','5','5',',','7','4','7','\0'};

    int firstSize = 0;//
    int secondSize = 0;//

    //new = 4 \0 \0
    char first[] = {'0', '\0'};//
    //new = 
    char second[] = {'0', '\0'};//
    char *first_ptr = first;
    char *second_ptr = second;

    int takingFirst = 1;
    int takingSecond = 0;

    int i;
    for (i = 0; i < strlen(asshat); i++)
    {
        if (asshat[i] != ',')
        {
            if (takingFirst == 1)
            {
                first_ptr[firstSize] = asshat[i];//ERROR here when you add 5 you s**t bricks
                firstSize++;
                if (asshat[i+1] != ',')
                {
                    char new[firstSize+2];
                    int k;
                    for (k = 0; k < strlen(first_ptr); k++)
                    {
                        new[k] = first_ptr[k];
                    }
                    new[firstSize] = '0';
                    new[firstSize+1] = '\0';
                    first_ptr = new;
                }
            }
            if (takingSecond == 1)
            {
                second_ptr[secondSize] = asshat[i];
                secondSize++;
                if (asshat[i+1] != '\0')
                {
                    char new[secondSize+2];
                    int k;
                    for (k = 0; k < strlen(second_ptr); k++)
                    {
                        new[k] = second_ptr[k];
                    }
                    new[secondSize+1] = '\0';
                    second_ptr = new;
                }
            }
        }
        else
        {
            takingFirst = 0;
            takingSecond = 1;
        }
    }
    printf("%d\n",strlen(first_ptr));
    printf("%c%c%c\n",first_ptr[0],first_ptr[1],first_ptr[2]);
    printf("%s\n",first_ptr);

    printf("%d\n",strlen(second_ptr));
    printf("%c%c%c\n",second_ptr[0],second_ptr[1],second_ptr[2]);
    printf("%s\n",second_ptr);
}

Answer 1

It’s very hard to read what your solution is doing. I tried reimplementing it to be simpler while maintaining your pointer play:

#include <stdio.h>

int 
main(int argc, char *argv[])
{   
  /* Keeping variable names consistent :) */
  char asshat[] = "456,747";
  char *first = asshat, *second = asshat, *c = asshat;

  while (*c) {
    if (*c == ',') {
      *c = '\0'; second = ++c;
    } else c++;
  }   
  printf("first: %s\nsecond: %s\n", first, second);
  return 0;
}   

This produces:

first: 456
second: 747