C++ Word finder and Word counter: List the words in a sentence and count the total number of words found

/*
PROGRAM: Word finder and Word counter
PURPOSE: List the words in a sentence and count the total number of words found
LANGUAGE: C++
AUTHOR: eternaltreasures
DATE: 2010 October 2
*/

#include <iostream>
#include <stdio.h>
#include <string>
using namespace std;

#define newline '\n'

char sentence [124];

int i;
int character_x;
int first_write_character = 0;
int wordcounter = 0;

void extractwords ()
{
 //Start testing the sentence from the first character until the null character \0
 for (i=0; sentence[i] != '\0'; i++)
 {
 //if a space is encountered, then write the words
  if (sentence[i] == ' ')
   {   
    wordcounter = wordcounter + 1;    
    for (character_x = first_write_character; character_x < i; character_x ++)
     {
      cout << sentence[character_x];
     }
       cout << newline;
    first_write_character = i + 1;
    }
  }
}

//once the program detects the null character or empty string \0
//then this is the last word in the sentence input from the user
void extractlastword ()
{
 wordcounter = wordcounter + 1;
 for (character_x = first_write_character; character_x < i; character_x ++)
 {
  cout << sentence[character_x];
 
 }
}

//this function displays the total word count in the given sentence
void countwords ()
{
 cout << newline;
 cout << newline;
 cout << "Total words found: " << wordcounter;
}

//this is the main function of execution in the program
int main ()
{
cout << newline;

cout << "Please enter a sentence: ";
cout << newline;
gets (sentence);

cout << newline;
cout << "List of words found:";
cout << newline;
   
extractwords ();

extractlastword ();

countwords ();

return 0;
}