77 lines
1.8 KiB
Markdown
77 lines
1.8 KiB
Markdown
|
---
|
||
|
|
title: Break Control Statement
|
||
|
|
localeTitle: 中断控制声明
|
||
|
|
---
|
||
|
|
# 中断控制声明
|
||
|
|
|
||
|
|
终止循环并开始执行紧跟循环的代码。如果你有嵌套循环， `break`语句将只结束它所在的循环。
|
||
|
|
|
||
|
|
```java
|
||
|
|
// Loop 1
|
||
|
|
for (int i = 0; i < 10; i++)
|
||
|
|
{
|
||
|
|
// Loop 2
|
||
|
|
for (int j = 0; j < 10; j++)
|
||
|
|
{
|
||
|
|
if (i == 5 && j == 5)
|
||
|
|
{
|
||
|
|
break; // Will terminate Loop 2, but Loop 1 will keep going
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
```
|
||
|
|
|
||
|
|
但是，如果您确实想要突破外部循环，可以使用标签退出：
|
||
|
|
|
||
|
|
```java
|
||
|
|
loop1: // This is a label
|
||
|
|
for (int i = 0; i < 10; i++)
|
||
|
|
{
|
||
|
|
// Loop 2
|
||
|
|
for (int j = 0; j < 10; j++)
|
||
|
|
{
|
||
|
|
if (i == 5 && j == 5)
|
||
|
|
{
|
||
|
|
break loop1; // Will break out of Loop 1, instead of Loop 2
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
```
|
||
|
|
|
||
|
|
 [运行代码](https://repl.it/CJZA/0)
|
||
|
|
|
||
|
|
在搜索数组中的元素时， `break`语句特别有用。使用下面代码中的`break`可以提高效率，因为一旦找到我们要查找的元素（ `searchFor` ），循环就会停止，而不是一直到达`arrayInts`的末尾。
|
||
|
|
|
||
|
|
```java
|
||
|
|
int j = 0;
|
||
|
|
int[] arrayOfInts = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9};
|
||
|
|
int searchFor = 5;
|
||
|
|
|
||
|
|
for (int i : arrayOfInts)
|
||
|
|
{
|
||
|
|
if (arrayOfInts[j] == searchFor)
|
||
|
|
{
|
||
|
|
break;
|
||
|
|
}
|
||
|
|
j++;
|
||
|
|
}
|
||
|
|
|
||
|
|
System.out.println("j = " + j);
|
||
|
|
```
|
||
|
|
|
||
|
|
Break语句也可以在while语句下使用。
|
||
|
|
|
||
|
|
```java
|
||
|
|
int i = 0;
|
||
|
|
int[] arrayOfInts = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9};
|
||
|
|
int searchFor = 5;
|
||
|
|
|
||
|
|
while(i < 10){
|
||
|
|
System.out.println("i = " + j);
|
||
|
|
if(arrayOfInts[i] > 7){
|
||
|
|
break;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
```
|
||
|
|
|
||
|
|
 [运行代码](https://repl.it/CJZC/0)
|