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

char * repeat_str(size_t count, const char * src)
{
   size_t len = strlen(src);
   char * result = (char *)malloc(sizeof(char) * len * count);

   for(size_t i = 0; i < count; i++)
      strncat(result, src, len);
  
   return result;
}

int main(void)
{
	char * result = repeat_str(4, "hello ");
	printf("Result: '%s' (success: %d)", result, (strcmp(result, "hello hello hello ") == 0));
}