void diff(FILE *infile1, FILE *infile2, FILE *outfile)
{
    char file1_line[MAX_LINE_LEN] = "";
    char file2_line[MAX_LINE_LEN] = "";
    int line_number = 0;
    int num_differences = 0;

    /* Read a line from each file */
    fgets(file1_line, MAX_LINE_LEN, infile1);
    fgets(file2_line, MAX_LINE_LEN, infile2);

    /* Change this into a loop through the infiles */
    for (line_number=1; line_number<=MAX_LINE_LEN; line_number++)
    {

    if ( strcmp goes here )
    {
    fprintf(outfile, "File 1 (%d):%s",
           line_number, file1_line);
    fprintf(outfile, "File 2 (%d):%s",
           line_number, file2_line);
    num_differences++;

    fgets(file1_line, MAX_LINE_LEN, infile1);
    fgets(file2_line, MAX_LINE_LEN, infile2);
    }
    }

    /* Print the number of differences to the screen */
    printf("Number of differences found: %d\n", num_differences);
}