Hi everyone, I am a high school student and will take c programming later on. Please tell me: 1. what is the meaning of "return 0;"? When will use it? 2. How to declare a variable that stores only positive integer values? Regards, Moldman

Typically, return 0 is used to terminate the main function of a C program - after having initialized it as int main(int argc, char argv) This is done so that you can pass parameters into the program, and to return values from the program. Typically, a return value of 0 means that the program finished correctly, and 1 (or any other integer value) means the the program finished with an error. To store only integer values in a variable it must be declared as unsigned. All the major numerical data types can be declared as unsigned; short, int, long, etc... Hope this helps, GL with the class.

Thanks a lot, lightning!

you're welcome, glad I could help :)

Sorry, I need to clarify my first answer. When I said: "To store only integer values in a variable it must be declared as unsigned. All the major numerical data types can be declared as unsigned; short, int, long, etc..." I SHOULD have said: "To store only POSITIVE values in a variable it must be declared as unsigned. All the major numerical data types can be declared as unsigned; short, int, long, etc..."