BLOCKS AND STATEMENTS

The

if then else

 Statement

14.8.2

14.8   The

if

 Statement

The

if

 statement allows conditional execution of a statement or a conditional

choice of two statements, executing one or the other but not both.

IfThenStatement:

if (

Expression

 )

Statement

IfThenElseStatement:

if (

Expression

 )

StatementNoShortIf

 else

Statement

IfThenElseStatementNoShortIf:

if (

Expression

 )

StatementNoShortIf

 else

StatementNoShortIf

The

Expression

 must have type

boolean

, or a compile time error occurs.

14.8.1   The

if then

 Statement

I took an early opportunity of testing that statement . . .

 Agatha Christie,

The Mysterious Affair at Styles

 (1920), Chapter 12

An

if

then

 statement is executed by first evaluating the

Expression

. If evaluation

of the

Expression

 completes abruptly for some reason, the

if

then

 statement

completes abruptly for the same reason. Otherwise, execution continues by mak 

ing a choice based on the resulting value:

If the value is

true

, then the contained

Statement

 is executed; the

if

then

statement completes normally only if execution of the

Statement

 completes

normally.

If the value is

false

, no further action is taken and the

if

then

 statement

completes normally.

14.8.2   The

if then else

 Statement

An

if

then

else

 statement is executed by first evaluating the

Expression

. If

evaluation of the

Expression

 completes abruptly for some reason, then the

if

then

else

statement completes abruptly for the same reason. Otherwise, execu 

tion continues by making a choice based on the resulting value:

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