why do i need to include to use them?

Question

I am new to C++ and trying to figure out how to use vector.

More specifically, I want to know when I need to use #include. I

Answer 1

You need to include the header file, to use any type of data/function. All the data types and functions in c++ are included in their own libraries.If you dont include the library, the c++ program won't know what you used, because it doesnt know they even excist.Its like :

You want to play with Jim's dog, but you dont know who Jim is, or what a dog is.