在给定条件为真时重复一个语句或一组语句，它在执行循环体之前判断条件，只要给定条件为真， while 循环语句就会重复执行目标语句。
while - 语法
以下是while循环的语法。
while(condition){ statement(s); }
while - 流程图
while - 示例
object Demo {
def main(args: Array[String]) {
//局部变量声明：
var a=10;
</span><span class="com">//while循环执行</span><span class="pln">
</span><span class="kwd">while</span><span class="pun">(</span><span class="pln"> a </span><span class="pun"><</span><span class="pln"> </span><span class="lit">20</span><span class="pln"> </span><span class="pun">){</span><span class="pln">
println</span><span class="pun">(</span><span class="pln"> </span><span class="str">"Value of a: "</span><span class="pln"> </span><span class="pun">+</span><span class="pln"> a </span><span class="pun">);</span><span class="pln">
a</span><span class="pun">=</span><span class="pln">a </span><span class="pun">+</span><span class="pln"> </span><span class="lit">1</span><span class="pun">;</span><span class="pln">
</span><span class="pun">}</span><span class="pln">
}
}
将上述程序保存在 Demo.scala 中。以下命令用于编译和执行该程序。
\>scalac Demo.scala \>scala Demo
value of a: 10 value of a: 11 value of a: 12 value of a: 13 value of a: 14 value of a: 15 value of a: 16 value of a: 17 value of a: 18 value of a: 19
