Constants

In programming, a constant is a value that cannot be changed during the execution of a program. It is similar to a variable, but unlike a variable, its value remains the same throughout the program's execution. Constants are often used to define fixed values or values that should not be changed for consistency or security reasons.

Constants are used in various programming languages, such as JavaScript, Python, and C++. Here is an example of defining a constant in JavaScript:

const PI = 3.14159;

In this example, the value of PI is defined as a constant and cannot be changed later in the program.

Constants are typically defined using uppercase letters to differentiate them from variables, which are often defined using lowercase letters. Here is an example of defining a constant in C++:

const int MAX_VALUE = 100;

In this example, the value of MAX_VALUE is defined as a constant and cannot be changed later in the program.

Using constants in programming can improve the readability and maintainability of code. By defining values as constants, it makes the code easier to understand, and it reduces the chance of errors caused by changing values that should not be changed.