crear un programa que desde un archivo que tiene una oración, buscar las palabras repetidas

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

int main(int argc, char *argv[])
{
    FILE *f;
    FILE *f1;
    char word[50];
    char word1[50];
    int i,j;
    int count;
    int found;

    f = fopen("file2.txt", "r");
    f1 = fopen("file1.txt", "w");

    while((fscanf(f, "%s", word)) != EOF)
    {
        count = 0;
        found = 0;
        while((fscanf(f1, "%s", word1)) != EOF)
        {
            if(strcmp(word, word1) == 0)
            {
                found = 1;
            }
        }
        if(found == 0)
        {
            fseek(f, 0, SEEK_SET);
            while((fscanf(f, "%s", word1)) !=