Programming and Problem Solving with Java

(^170) | Selection and Encapsulation
What we really want to do is turn the elseclause into a sequenceof statements. This is easy.
Recall from Chapter 2 that the compiler treats the block (compound statement)
{

}

as a single statement. If you put a{}pair around the sequence of statements you want in a

branch of theifstatement, the sequence of statements becomes a single block. For example:

if (divisor != 0)

result = dividend / divisor;

else

{

System.out.println("Division by zero is not allowed.");

result = Integer.MAX_VALUE;

}

If the value ofdivisoris zero, the computer both displays the error message and sets the value

ofresulttoInteger.MAX_VALUEbefore continuing with whatever statement follows theifstatement.

Blocks can be used in both branches of an if-elsestatement. For example:

if (divisor != 0)

{

result = dividend / divisor;

System.out.println("Division performed.");

}

else

{

System.out.println("Division by zero is not allowed.");

result = Integer.MAX_VALUE;

}

When you use blocks in an ifstatement, you must remember a rule of Java syntax: Never use

a semicolon after the right brace of a block. Semicolons are used only to terminate simple state-

ments such as assignment statements and method calls. If you look at the earlier examples,

you won’t see a semicolon after the right brace that signals the end of each block.

The if Form

Sometimes you run into a situation where you want to say, “Ifa certain condition exists,

perform some action; otherwise, don’t do anything.” In other words, you want the computer

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