Thread: to Reverse the words in the string... help.. I just can't see the error...

The process can be as simple or complex as you'd like. For instance, a simpler but more difficult to understand method would be to use two pointers and walk down the string. When the end pointer finds a space or the end of the string, reverse from the start pointer to the end pointer and assign the end pointer to the start pointer. Lather, rinse, repeat.

Code:

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

static void revstr ( char *start, char *end )
{
  char hold;

  while ( start < end ) {
    hold = *start;
    *start = *end;
    *end = hold;

    start++;
    end--;
  }
}

int main ( void )
{
  char buf[] =  "Hello world haha";
  char *last = buf + sizeof buf;
  char *start = buf;
  char *end;

  for ( end = start; end != last; start = ++end ) {
    while ( *end != '\0' && !isspace ( *end ) )
      end++;

    revstr ( start, end - 1 );
  }

  printf ( "%s\n", buf );

  return 0;
}

-Prelude