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

void strcat333(char *s1, char *s2, char **result) {
  if (s1 == NULL || s2 == NULL || result == NULL) {
    printf("No null arguments\n");
    return;
  }

  int s1_len = strlen(s1);
  int s2_len = strlen(s2);
  int res_len = s1_len + s2_len + 1; // +1 for '\0'
  char *res_str = (char *) malloc(res_len);
  if (res_str == NULL) {
    printf("Malloc failed\n");
    return;
  }

  char *pos_ptr = res_str;
  for (int i = 0; i < s1_len; i++) {
    *pos_ptr = *s1;
    pos_ptr++;
    s1++;
  }

  for (int j = 0; j <= s2_len; j++) {
    *pos_ptr = *s2;
    pos_ptr++;
    s2++;
  }

  *result = res_str;
}

int main(int argc, char **argv) {
  char *str1 = "CSE";
  char *str2 = "333";

  char *res;
  strcat333(str1, str2, &res);

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

  free(res);
}