Boolean Expressions

This chapter introduces relational and logical operators. It also discusses the use of these operators to write Boolean expressions.

4. &&


flour >= 4  true

sugar >= 2  false 


Examine this part of the program:

// check that there is enough of both ingredients
if ( flour >= 4 && sugar >= 2 )
System.out.println("Enough for cookies!" );
System.out.println("sorry...." );

For you to have enough ingredients, both relational expressions must be true. This is the role of the && (and-operator) between the two relational expressions. The && requires that both

flour >= 4 


sugar >= 2 

are true for the entire expression to be true. The entire question must be true in order for the true branch to execute.

The and operator && is a logical operator. A logical operator examines two true/false values and outputs a single true/false value.

Question 4:

What is printed if the user enters 6 for flour and 4 for sugar?