Java

TOPIC 32 – BOOLEAN FUNCTIONS

LESSON NOTE

DEFINITION

A Boolean function is simply a function that returns either true or false.

EXAMPLE

The function below returns true whenever the provided parameter is larger than 100. Otherwise, it returns false.

public static boolean isBiggerThanAHundred(int x)

{

if (x > 100)

{

return true;

}

else

{

return false;

}

}

BOOLEAN FUNCTION CALL AS CONDITION

Remember that a condition is simply an expression that evaluates to either true or false. Therefore, a Boolean function call can be used as a condition.

EXAMPLE

The Boolean function from above is being used as a Boolean expression inside the if statement below:

if (isBiggerThanAHundred(mark))

{

…

}

HIGHER LEVEL CODING

Boolean functions often allow programmers to think about programs at a higher level by hiding some of the details inside functions. The function names can also be chosen to make the program seem like English.

EXAMPLE – HIGHER LEVEL THINKING

if (gameIsOver())

{

if (newNewHighScore(score))
{

displayHighScoreScreen();

}

displayRestartScreen();

}