C prog to chck correctness

If you don't have to care about the pre-processor or comments then the job is rather easy. Opening a brace, parenthesis, or bracket is just looking for the occurrence of the character. Closing one of them is essentially the same, although using a different character, with the caveat that it must be open first. If not then it is incorrect. Also, any of those left open at the end of the file are incorrect also. In a real parser, yes, a stack would be used for this but for your purpose it can be much simpler. All you need are counters three counters. Start the counters at zero, increment when an opening character is found, and decrement them when the corresponding closing character is found. Start by opening the file in text mode, fopen can do this. Then read single characters at a time and evaluate each one as noted above. The function fread can do this. Remember to call fclose when the end of the file is reached.

You can use a linked list with a new element with type information for ever opening element and removing it for every closing element. A double linked list should be better.