Hi,Please be kind as it's my very first post.

OK, here's my problem. I have a (biggish) C program which compiles fine (using Borland C++ Version 5.01). Now when I run it, it crashes (floating point exception) at some point. I have identified the function in which it crashes but then when I try to view some intermediate variables in the function using a simple "printf" problem, then surprisingly, the program then runs through to completion wihout any problem. If I comment out the "printf" line, then it crashes again!! So it is very difficult for me to then debug in further detail by printing on screen any other variables as the "printfs" seem to cause the program to execute correctly, and removing them causes the problem. I haven't posted any of the code as I just want to know if anyone has encountered such a problem before and if they have any suggestions on what might be the cause.

Thanks

Nope. Never saw that.

And totally impossible for us without some code.

You're doing something wrong. What else is there to say with the info you've given?

You need to read that very hard to miss post at the top of the forum. Especially Guideline 1.4

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Please read http://www.gidforums.com/t-5566.html. They were written to help you create a request that is readable and has enough information we can actually tell what you need help with.

Yes, I have.

The cause was a bug in my code (in at least one case it was the infamous "buffer overflow" caused by an out-of-range index for an array).

Now, if you can reduce your "biggish" program to a smaller amount of code that exhibits the problem, post it. If there is no way to reduce your program to a smaller amount that still exhibits the problem, then I suggest one of the following:

1. (Top-down design)
a. Organize your program so that you can start testing with a main program that calls various functions. For starters, just put some dummy stuff in the various functions. For functions that return values, make them return something that your main program can accept, and go on to the next step.

b. Implement (write code) for the functions that you can test as you go.

2. (Bottom-up design)
a. Define all of the functions that you need to use. Write a dummy main program for each that gives the function some realistic argument and tests the return value (and/or side-effects) of each function.

b. After testing each function, put it into place in your "main" main program and go on to the next function.

3. (Top-down design, bottom-up implementation)

Combination of the above


In any case, before you start writing code, think about how you are going to test each stage of the development and think about how you are going to test the final product.

Regards,

Dave