tcpl-ex-5-3.c

/*
 * Exercise 5-3. Write a pointer version of the function strcat that we 
 * showed in Chapter 2:strcat(s, t) copies the string t to the end of s.
 */
#include <stdio.h>


void my_strcat(char *s, char *t)
{
	while (*s)
		s++;
	while (*s++ = *t++)
		;
}

int main(void)
{
  char testbuff[128];
 
  char *test[] =
  {
    "",
    "1",
    "12",
    "123",
    "1234"
  };
 
  size_t numtests = sizeof test / sizeof test[0];
  size_t thistest;
  size_t inner;
 
  for(thistest = 0; thistest < numtests; thistest++)
  {
    for(inner = 0; inner < numtests; inner++)
    {
      strcpy(testbuff, test[thistest]);
      my_strcat(testbuff, test[inner]);
 
      printf("[%s] + [%s] = [%s]\n", test[thistest], test[inner], testbuff);
    }
  }
 
  return 0;
}