How to protect program before incorrect input data?

[piruk]

I have to write a program in c++, which write lots of data. I use int,
double and string. How to protect the program before incorrect input
data? What is the best way?

piruk

 

[Ian Collins]

I have to write a program in c++, which write lots of data. I use int,
double and string. How to protect the program before incorrect input
data? What is the best way?

Please don't multi-post on Usenet, cross-post if you must, but don't
multi-post.

See alt.comp.lang.learn.c-c++ for a good answer.