S14 Answer

/* Puzzle S14 — Ends with */
#include <stdio.h>
#include <stdlib.h>

int endsWith( char const *bigString, char const *endString )
{
  /* deal with special cases: empty strings */
  if ( *endString == '\0' ) return 1;
  if ( *bigString == '\0' ) return 0;

  /* create two pointers that will run backwards through the strings */
  char const *bs = bigString;
  char const *es = endString;

  /* find the last character of bigString */
  while ( *bs ) bs++ ; bs-- ;

  /* find the last character of endString */
  while ( *es ) es++ ; es-- ;

  /* check the two tails, working back to front */
  while ( bs != bigString &&  es != endString &&  *bs == *es )
  {
    bs--; es--;
  }

  /* success, if first char of endString matches corresponding */
  /* character of bigString */
  return *bs == *es && es == endString ;
}

int main(int argc, char *argv[])
{
 char *trials[][2] =
  {
    {"abcdef", "f"},
    {"abcdef", "ef"},
    {"abcdef", "def"},
    {"abcdef", "cdef"},
    {"abcdef", "abcdef"},
    {"abcdef", "a"},
    {"abcdef", "abc"},
    {"abcdef", "xabcdef"},
    {"abcdef", "xyzabcdef"},
    {"abcdef", "rats"},
    {"abbccddeef", "cc"},
    {"abcdefg", "g"},
    {"applecart", "cart"},
    {"green", "apple"},
    {"apple", ""},
    {"", "rats"}, 
    {"",""}
  };

  int j; char *loc;
  for ( j=0; j<sizeof(trials)/sizeof(trials[0]); j++ )
  {
    int result = endsWith( trials[j][0], trials[j][1] ) ;
    if ( result )
      printf("%s\t ends with \t%s\n", trials[j][0], trials[j][1]  );
    else
      printf("%s\t does not end with\t%s\n", trials[j][0], trials[j][1]  );
  }

  system("PAUSE");
  return 0;
}

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