knr/5.4.c

/* Write the function strend(s,t), which returns 1 if the string t occurs at the end of the string s, and zero otherwise.  */
#include <stdio.h>
enum { FALSE, TRUE };

int equal (a,b);
int strend(s,t);

int main(int argc, char** argv)
{
  if (argc == 3)   printf("%s %s",argv[1],argv[2]);
  return strend(argv[1],argv[2]);
}

int strend(char s[],char t[])
{
  //figure out thow long t is;
  int sizes = 0;
  char *sptr = s;
  if (sptr == 0)
    return -1;
  while(*sptr)
    {
	 sizes++;
	 sptr++;
    }

  int sizet = 0;
  char *tptr = t;
  if (tptr == 0)
    return -1;
  while(*tptr)
  {
    sizet++;
    tptr++;
  }

  if (sizes < sizet) return 0;
  else
    {
	 char *tptr2 = t;
	 char *sptr2 = sptr-sizet; //off by 1?
	 while ((*sptr2) && equal(sptr2,tptr2)) 
	   {
	    sptr2++;
	    tptr2++;
	   }
	 return (*tptr2 == 0);
   }
  
  //figure out how long s is;
  //if t can't fit in s return 0;
  //if it *is* long enough, go back far enough and start checking
  //if the whole thing is there return 1
  
}

int equal (char* a, char* b)
{
  if (*a == *b )
    return TRUE;
  else return FALSE;
}