Variables in c++
- C++ allows you to store values in variables. Each variable is identified by a variable name.
- Additionally, each variable has a variable type. The type tells C++ how the variable is going to be used and what kind of numbers (real, integer) it can hold.
- A variable must be defined before you can use it in a program.
- When you define a variable the type is specified and an appropriate amount of memory reserved.
- This memory space is addressed by reference to the name of the variable.
- Some programming languages do not require programmers to declare variables before they are used; the type of a variable is determined by how the variable is used.
- Some languages allow the same variable to assume different types as its use differs in different parts of a program.
Before you can use a variable in C++, it must be defined in a declaration statement. A variable cannot be used unless it is declared.
A variable declaration serves three purposes:
- It defines the name of the variable.
- It defines the type of the variable (integer, real, character, etc.).
- It gives the programmer a description of the variable.
type name; // comment
Type is one of the C++ variable types (int, float, etc.) Name is any valid variable name. The comment explains what the variable is and what it will be used for.
Variable declarations come just before the main() line at the top of a program.