Answer S8

/* Puzzle S08 --  trim */
#include <stdio.h>
#include <stdlib.h>

void trim( char *p )
{
  /* Return immediately if empty string */
  if ( !*p ) return;

  /* Find the null at the end of the string */
  char *end = p;
  while ( *end ) end++ ;

  /* Find the first non-white character, if any */
  char *start = p;
  while ( *p && isspace( *start ) ) start++ ;

  /* Make the string empty if it is all whitespace */
  if ( start==end )
  {
    *p = '\0';
    return;
  }

  /* Find the last non-white character */
  while ( isspace( *--end ) ) ;

  /* Put a null after the last non-white character */
  *++end = '\0' ;

  /* Move characters down to the front of the buffer */
  while ( *p++ = *start++ ) ;
}

int main()
{
  char buffer[ 100 ];
  char *trials[] =
  {
  "    The game is afoot!   ",
  "The    game  is    afoot!",
  "   The game is afoot!",
  "The game is afoot!     ",
  "\n\nNewLines and tabs count as Whitespace\n\n\t\t",
  "\n\tInternal\ttabs\t \tShould Remain  \t",
  "",
  "Empty strings should pass right through",
  "             \t\n\t      ",
  " ",
  "              ",
  "Strings of all whitespace should be reduced to empty"
  };

  int j ;
  for ( j=0; j<sizeof(trials)/sizeof(char *); j++ )
  {
    strcpy( buffer, trials[j] );
    trim( buffer );
    printf("-->%s<--\n", buffer );
  }

  system("PAUSE");
  return 0;
}