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Selection is the second programming construct. In programming, there are occasions when a decision needs to be made. Selection is the process of making a decision. The result of the decision decides which path the program will take next.

For example, a program could tell a user whether they are old enough to learn how to drive a car. If the user's age meets the required driving age, the program would follow one path and execute one set of instructions. Otherwise, it would follow a different path and execute a different set of instructions.

Selection works by testing a condition. The test gives a Boolean result - TRUE or FALSE. If the result is TRUE, the program follows one path - otherwise it follows another.

In programming, selection is implemented using IF THEN or IF THEN ELSE statements:

SEND ‘How old are you?‘ TO DISPLAY
                    RECEIVE age FROM (INTEGER) KEYBOARD
                    IF age > 16 THEN
                         SEND ‘You are old enough to drive a car!’
                         TO DISPLAY
                    ELSE
                         SEND ‘Come back when you are older!’
                         TO DISPLAY
                    END IF

In the pseudo-code program above, the path the program takes depends on the condition. A variable - in this case age - is used to test the condition.

If the value of age is greater than 16, the result of the tested condition is TRUE and the program follows the first path, which follows the statement THEN. This path informs the user that they are old enough to drive.

If the value of age is less than 16, the result is FALSE and the program follows the second path, which follows the statement ELSE. This path informs the user that they are not yet old enough to drive.

The statement END IF ends the selection.