有人能告诉我break语句和continue语句的区别吗?


当前回答

break语句会导致它所应用的语句(switch、for、do或while)的终止。

continue语句用于结束当前循环迭代并将控制权返回给循环语句。

其他回答

为了在满足条件时阻止执行任何东西,应该使用continue,如果满足条件,则应该使用break退出循环。

例如下面提到的代码。

 for(int i=0;i<5;i++){

        if(i==3){

           continue;

        }
       System.out.println(i);
     }

上面的代码将打印结果:0 1 2 4

现在考虑这段代码

 for(int i=0;i<5;i++){


            if(i==3){

                break;

            }
            System.out.println(i);
         }

这段代码将输出0 12

这就是continue和break的基本区别。

简单的程序,了解继续和中断之间的区别

当使用continue时

    public static void main(String[] args) {
    System.out.println("HelloWorld");
    for (int i = 0; i < 5; i++){
        System.out.println("Start For loop i = " + i);
        if(i==2){
            System.out.println("Inside if Statement for i = "+i);
           continue;
        }
        System.out.println("End For loop i = " + i);
    }
    System.out.println("Completely out of For loop");
}


OutPut:
HelloWorld
Start For loop i = 0
End For loop i = 0
Start For loop i = 1
End For loop i = 1
Start For loop i = 2
Inside if Statement for i = 2
Start For loop i = 3
End For loop i = 3
Start For loop i = 4
End For loop i = 4
Completely out of For loop

什么时候使用break

public static void main(String[] args) {
    System.out.println("HelloWorld");
    for (int i = 0; i < 5; i++){
        System.out.println("Start For loop i = " + i);
        if(i==2){
            System.out.println("Inside if Statement for i = "+i);
           break;
        }
        System.out.println("End For loop i = " + i);
    }
    System.out.println("Completely out of For loop");
}

Output:
HelloWorld
Start For loop i = 0
End For loop i = 0
Start For loop i = 1
End For loop i = 1
Start For loop i = 2
Inside if Statement for i = 2
Completely out of For loop
System.out.println ("starting loop:");
for (int n = 0; n < 7; ++n)
{
    System.out.println ("in loop: " + n);
    if (n == 2) {
        continue;
    }
    System.out.println ("   survived first guard");
    if (n == 4) {
        break;
    }
    System.out.println ("   survived second guard");
    // continue at head of loop
}
// break out of loop
System.out.println ("end of loop or exit via break");

这将导致以下输出:

starting loop:
in loop: 0
    survived first guard
    survived second guard
in loop: 1
    survived first guard
    survived second guard
in loop: 2
in loop: 3
    survived first guard
    survived second guard
in loop: 4
    survived first guard
end of loop or exit via break

你可以标记一个块,不仅仅是一个for循环,然后从一个嵌套块到一个外部块。在少数情况下,这可能是有用的,但一般情况下,你会尽量避免这样的代码,除非程序的逻辑比下面的例子更好理解:

first:
for (int i = 0; i < 4; ++i) 
{
    second:
    for (int j = 0; j < 4; ++j) 
    {
        third:
        for (int k = 0; k < 4; ++k) 
        {
            System.out.println ("inner start: i+j+k " + (i + j + k));
            if (i + j + k == 5)
                continue third;
            if (i + j + k == 7)
                continue second;
            if (i + j + k == 8)
                break second;
            if (i + j + k == 9)
                break first;
            System.out.println ("inner stop:  i+j+k " + (i + j + k));
        }
    }       
}

因为它是可能的,但这并不意味着你应该使用它。

如果你想以一种有趣的方式混淆你的代码,你不选择一个有意义的名字,而是http:,并在它后面加上一个注释,看起来很陌生,就像源代码中的网络地址:

http://stackoverflow.com/questions/462373
for (int i = 0; i < 4; ++i) 
{
     if (i == 2) 
         break http;

我猜这是约书亚·布洛赫做的小测验。:)

考虑以下几点:

int n;
for(n = 0; n < 10; ++n) {
    break;
}
System.out.println(n);

Break导致循环终止,n的值为0。

int n;
for(n = 0; n < 10; ++n) {
    continue;
}
System.out.println(n);

Continue使程序计数器返回到循环的第一行(检查条件,n的值为增量),n的最终值为10。

还应该注意的是,break只终止它所在循环的执行:

int m;
for(m = 0; m < 5; ++m)
{
    int n;
    for(n = 0; n < 5; ++n) {
        break;
    }
    System.out.println(n);
}
System.out.println(m);

会输出什么效果

0
0
0
0
0
5

break语句跳出循环(要执行的下一个语句是右大括号之后的第一个语句),而continue语句在下一个迭代中开始循环。