Hi there! I'm having a bit of trouble with a program I'm trying to write. What I want to do is have two files entered at the command line and then the program will see if they are the same or not (checking character by character). If they are not the same the program will display the letter number where the two files differ. My problem is I'm having difficulty trying to figure out how to write a loop that will read the two files and then compare them character by character. My thoughts were this:

1. Open both text files
2. Read each file into a string buffer
3. Go through the string buffers and compare them to each other character by character until EOF or a different character is present

I know what I want to do but actually writing the code is what is confusing me. Any help would be greatly appriciated. Thanks.

Hello trust.

I think your problem would be better solved by reading the files char by char and comparing them. That way, you don't need to worry about trying to allocate a string buffer and what size it needs to be for the file etc.

I would set a forever loop that would break based upon different conditions. Inside that loop do:

• Read char from first file(char1=fgetc(fp1))
• Read char from second file(char2=fgetc(fp2))
• Check either for eof.
• If both are eof, set compare to 0 (files are equal) and break
• If first file is eof, set compare to -1 (file is less than file2) and break
• If second file is eof, set compare to 1 (file2 is less than file1) and break
• if char1 is less than char2 set compare to -1 and break
• if char2 is less than char1 set compare to 1 and break
• otherwise keep on looping.
• You could also set a counter that would be incremented to tell what position any difference occured at.

Overall, this isn't too terribly difficult of a program.

Good luck!
d

Thanks dsmith! Your suggestions worked out perfectly.