## Boolean Expressions

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

### 23. Precedence of NOT

Answer:No. In this defective fragment, the NOT (the !) applies directly to cost.

# Precedence of NOT

The NOT operator has high precedence, so it is done before arithmetic and relational operators unless you use parentheses. Examine the following:

!cost < 50 -----  illegal: can't use ! on an arithmetic variable

Since ! has high precedence, the above says to apply it to cost. This which won't work, because cost is an integer and NOT applies only to boolean values.

Question 24:You need new shoes. But all you can afford is a pair of shoes that costs less than fifty dollars.Look at these fragments of code. Does each do the same thing?if ( cost < 50  )
System.out.println("Acceptable shoes");
else
System.out.println("Reject these shoes");
if ( !(cost < 50)  )
System.out.println("Reject these shoes");
else
System.out.println("Acceptable shoes");
if (  cost >= 50 )
System.out.println("Reject these shoes");
else
System.out.println("Acceptable shoes");
if (  !(cost >= 50)  )
System.out.println("Acceptable shoes");
else
System.out.println("Reject these shoes");
Mentally try a few costs with each fragment to see if they are equivalent.