What is a Variable? The easiest way to explain variables to kids is with real-world examples. The number 3 is a constant. If you say there are 3 apples in a basket, everyone knows exactly how many apples they should expect to see.

In most programming languages, a variable is a container that holds information that you can access. You can think of a variable as a box that contains something. You can open the box to find out what is inside, or even put something else into the box. In some ways, human memory and computer memory are similar.

You can assign a value to a routine variable in any of the following ways:

1. Use a LET statement.
2. Use a SELECT INTO statement.
3. Use a CALL statement with a procedure that has a RETURNING clause.
4. Use an EXECUTE PROCEDURE INTO or EXECUTE FUNCTION INTO statement.

The most common form of statement in a program uses the assignment operator, =, and either an expression or a constant to assign a value to a variable: variable = expression; variable = constant; The symbol of the assignment operator looks like the mathematical equality operator but in C++ its meaning is different.

type variable = value; Where type is one of Java’s types (such as int or String ), and variable is the name of the variable (such as x or name). The equal sign is used to assign values to the variable.

Constants. In some languages, it is possible to define special variables which can be assigned a value only once – once their values have been set, they cannot be changed. We call these kinds of variables constants.

9 types

Constant Variables Using const you can define variables whose values never change. You MUST assign an initial value into a constant variable when it is declared.