I am trying to write a program which opens up a text file, reads from the file, changes upper case to lower case, and then counts how many times that word has occurred in the file and prints results into a new text file.

My code so far is as follows: 

```
#include <stdio.h>
#include <stdlib.h>
#include <conio.h>
#include <ctype.h>
#include <string.h>

int main()
{

    FILE *fileIN;
    FILE *fileOUT;
    char str[255];
    char c;
    int i = 0;

    fileIN = fopen ("input.txt", "r");
    fileOUT = fopen ("output.txt", "w");

    if (fileIN == NULL || fileOUT == NULL)
    {
        printf("Error opening files\n");
    }

    else
    {
        while(! feof(fileIN)) //reading and writing loop
        {
            fscanf(fileIN, "%s", str); //reading file

            i = 0;
            c = str[i];
            if (isupper(c)) //changing any upper case to lower case
            {
                c =(tolower(c));
                str[i] = putchar(c);
            }

            printf("%s ", str); //printing output

                            fprintf(fileOUT, "%s\n", str); //printing into file
        }

        fclose(fileIN);
        fclose(fileOUT);
    }
    getch();
}

```

the input.txt file contains the following "The rain in Spain falls mainly in the plane"
Don't ask why.
After the running of the program as is the output would look like:
the
rain
in
spain
falls
mainly
in
the
plane

I have managed to lower case the upper case words. I am now having trouble understanding how I would count the occurrences of each word. eg in the output I would want it to say "the 2" meaning 2 had appeared, this would also mean that i do not want any more "the" to be stored in that file.

I am thinking strcmp and strcpy but unsure how to use those the way i want.

Help would be much appreciated

(Sorry if formatting bad)