C++ Lessons : 6.3. Constant Variables

[quix]

Constants

When you do not want others (or yourself) to change existing variable values, use the const keyword (this will declare the variable as "constant", which means unchangeable and read-only

Example

const int myNum = 15;  // myNum will always be 15
myNum = 10;  // error: assignment of read-only variable 'myNum'

You should always declare the variable as constant when you have values that are unlikely to change:

Example

const int minutesPerHour = 60;
const float PI = 3.14;