Information Technology Reference
In-Depth Information
The while Loop
The
while
loop is a simple loop construct in which the test expression is performed at the top
of the loop. The syntax of the
while
loop is shown here, and is illustrated in Figure 9-6.
Firs ,
TestExpr
is evaluated.
f
TestExpr
evaluates to
false
, then execution continues after the end of the
while
loop.
Otherwise, when
TestExpr
evaluates to
true
, then
Statement
is executed, and
TestExpr
is
evaluated again. Each time
TestExpr
evaluates to
true
,
Statement
is executed another
time. The loop ends when
TestExpr
evaluates to
false
.
while(
TestExpr
)
Statement
Figure 9-6.
The while loop
The following code shows an example of the
while
loop, where the test expression variable
starts with a value of
3
and is decremented at each iteration. The loop exits when the value of
the variable becomes
0
.
int x = 3;
while( x > 0 )
{
Console.WriteLine("x: {0}", x);
x--;
}
Console.WriteLine("Out of loop");
The output from this code is the following:
x: 3
x: 2
x: 1
Out of loop
