concat

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

char *concat(int n, ...) {
  va_list al;
  va_start(al, n);
  int len = 1;
  char *res = calloc(sizeof(char), n);
  for (int i = 0; i < n; i++) {
    char *s = va_arg(al, char*);
    len += strlen(s) + 1;
    res = realloc(res, sizeof(char) * len);
    strcat(res, s);
    strcat(res, " ");
  }
  va_end(al);
  return res;
}


int main(void) {
  char *res = concat(3, "asd", "qwerty", "6543210");
  puts(res);
  free(res);
  return 0;
}