Thread: doubt regarding C structure in linux

Show us the code.

> error: ISO C++ forbids declaration of ‘AAA’ with no type
And you posted on the C forum because?

Step 1 is decide whether you're programming in C or C++.

At the moment, you're using a good C++ compiler on Linux, and I guess a really old compiler on windows (not Turbo C surely - bet it is, it seems a popular choice for no good reason)

> When I write code on windows platform then I have no need to write return type in prototype and it compile and run
You can get away with this in old C.
In new C, implicit types are deprecated (meaning you should not do it, but it won't shut the compiler up).
You could never have implicit types in C++.

> and also explain me what should I kept in mind before coding in linux...
Make sure you actually know ANSI C.
And not the dialect C which you're trying to use at present.

When you know ANSI C, the issue of "which OS / Compiler" pretty much goes away.