java for 冒号 java for里面的冒号

用于循环中集合元素的遍历

for(元素变量:元素集合)

{

程序块；

}

解释：如果元素集合中所有元素都被遍历则结束此循环，否则执行程序块。

程序示例：

importjava.util.*;

publicclasssample{
privatevoidprint()
{
String[]str={"*************************************",
"Thesampleshowfourusagesof':'",
"1.switchsentence","2.?condition",
"3.continueskipping",
"4.elementreachinthecollection",
"*************************************"};

for(Stringe:str)
System.out.println(e);
}

publicstaticvoidmain(String[]args)
{
Randomrand=newRandom(10);
intval=0;
booleantmp=false;

label:
for(inti=0;i<10;)
{
switch(i)
{
case0:
case1:
case2:
System.out.println("forloop"+i+"");
i++;
break;
default:
System.out.println();
while(true)
{
val=rand.nextInt(10);
if(val>5?true:false)
{
i=10;
System.out.println();
continuelabel;
}
System.out.println("[continuewhileloop]"+"val="+val);
}
}
}
samples=newsample();
s.print();
}
}

运行结果：

forloop0
forloop1
forloop2

[continuewhileloop]val=3
[continuewhileloop]val=0
[continuewhileloop]val=3
[continuewhileloop]val=0

*************************************
Thesampleshowfourusagesof':'
1.switchsentence
2.?condition
3.continueskipping
4.elementreachinthecollection
*************************************