大家好，又见面了，我是你们的朋友全栈君。
一般在的，while, for 这样含有循环体的语句中，某些情况下我们会需要立即跳出当前循环。这时使用break语句就可以实现直接从当前循环体直接跳出开始执行while, for语句的下一条语句。
另外，break 这种可以从一段复合语句中跳出的功能也被switch 广泛借用，来跳过switch 复合语句，也就是被花括号框住的代码块中剩余的部分，转去执行switch 语句的下一条语句。因此在switch 中，break 常被用来控制控制流跳出，使得switch 在运用上更加灵活。
而Continue 略不同于break 。虽然同样在while, for 语句中体现出“跳过”的效果。但continue是跳过循环体的剩余部分，而后重新执行循环体的句头而非下一条语句。
另continue使用范围被限制在循环体中，不可用于switch。
我们可以通过一些简单的代码来验证他们的效果：
break 语句在while…do 句型中的效果：
#include <stdio.h>
//break 在while、for、switch语句中的运用
int main (){
//break in while...do
//初始化 initialize
int tmp = 0;
puts ( "while criculation\n" );
//while循环
while ( tmp <= 5 ){//while循环5次
printf_s ( "%d\t", tmp );
printf_s ( "%d\n", tmp );
tmp++;
}//end while
//初始化 initialize
tmp = 0;
puts ( "\nwhile circulation, execute the break when tmp = 3\n" );
//while循环
while ( tmp <= 5 ){//while循环5次
printf_s ( "%d\t", tmp );
if ( 3 == tmp ){//当tmp为3时，执行break
puts ( "break...");
break;
}//end if
printf_s ( "%d\n", tmp );
tmp++;
}//end while
}
相似的，在do…while 语句中的效果：
#include <stdio.h>
//break 在while、for、switch语句中的运用
int main (){
//break in do...while
//初始化 initialize
int tmp = 0;
puts ( "while criculation\n" );
//while循环
do{//while循环5次
printf_s ( "%d\t", tmp );
printf_s ( "%d\n", tmp );
tmp++;
}while ( tmp <= 5 );//end while
//初始化 initialize
tmp = 0;
puts ( "\nwhile circulation, execute the break when tmp = 3\n" );
//while循环
do{//while循环5次
printf_s ( "%d\t", tmp );
if ( 3 == tmp ){//当tmp为3时，执行break
puts ( "break...");
break;
}//end if
printf_s ( "%d\n", tmp );
tmp++;
}while ( tmp <= 5 );//end while
}
而break 在多重嵌套的while语句中
#include <stdio.h>
//break在while多重嵌套中的使用效果
int main () {
//initialize
int tmp = 0, loop = 0;
puts ( "multiple while nesting" );
//the first layer while
while ( loop <= 2 ){
loop++;
puts ( " in the first layer while");
//the second layer while
while ( tmp <= 2 ){
tmp++;
puts ( "\tin the second while");
if ( tmp >= 3){// execute break when tmp >= 3
puts ( "\tbreak");
break;
}//end if
puts ( "\tout of the second while");
}//end while
puts ( "out the frist layer while");
}//end while
}
break在for语句中体现：
#include <stdio.h>
//break 在while、for、switch语句中的运用
int main (){
//break in for
//if there is no break
puts ( "if there is no break ");
for (int tmp = 1; tmp <= 5; tmp++){//5 loops
printf_s ( "\nthis is No.%d", tmp );
}//end for
//when we add break
puts ( "\n\nexecute the break when tmp = 2");
for (int tmp = 1; tmp <= 5; tmp++){//5 loops
printf_s ( "\nthis is No.%d", tmp );
if ( 2 == tmp ){//execute when tmp = 5
puts ( "\tbreak" );
break;
}//end if
}//end for
}
在switch 中的运用：
#include <stdio.h>
//break 在while、for、switch语句中的运用
int main (){
//break in switch
//initialize
int tmp = 1;
//a switch without break
puts ( "a switch without break");
switch ( tmp ){
case 0:
puts ( "0");
case 1:
puts ( "1");
case 2:
puts ( "2");
case 3:
puts ( "3");
case 4:
puts ( "4");
case 5:
puts ( "5");
default:
puts ( "switch over\n");
}//end switch
//add break before case 4
puts ( "add break before case 4" );
switch ( tmp ){
case 0:
puts ( "0");
case 1:
puts ( "1");
case 2:
puts ( "2");
case 3:
puts ( "3");
break;
case 4:
puts ( "4");
case 5:
puts ( "5");
default:
puts ( "switch over");
}//end switch
}
continue 在while 循环中的效果体现：
#include <stdio.h>
//比较验证continue在while、for语句中的运用
int main () {
//initialize
int tmp = 0;
puts ( "while circulation" );
//while with out continue
while ( tmp <= 5 ){
tmp++;
printf_s ( "%d\t", tmp );
printf_s ( "%d\n", tmp );
}//end while
//initialize
tmp = 0;
puts ( "\nwhile loop with the continue statement");
//while loop with the continue statement
while ( tmp <= 5 )
{
tmp++;
printf_s ( "%d\t", tmp );
if ( tmp >= 3 ){//when tmp >= 3, excute continue
puts ( "" ); // 保证输出结果的规整
continue;
}//end if
printf_s ( "%d\n", tmp );
}//end while
}
continue在多重的while循环中表现出的作用范围同break一致，只对其所在的最近一级嵌套起作用。
#include <stdio.h>
//continue在while多重嵌套中的使用效果
int main () {
//initialize
int tmp = 0, loop = 0;
puts ( "multiple while nesting" );
//the first layer while
while ( loop <= 2 ){
loop++;
puts ( " in the first layer while");
//the second layer while
while ( tmp <= 2 ){
tmp++;
puts ( "\tin the second while");
if ( tmp >= 2){// execute continue when tmp >= 3
puts ( "\tcontinue");
continue;
}//end if
puts ( "\tout of the second while");
}//end while
puts ( "out the frist layer while");
}//end while
}
而尝试在switch 中使用continue 则会直接报错，指明continue 只能用于循环体
#include <stdio.h>
//continue 在while、for、switch语句中的运用
int main (){
//continue in switch
//initialize
int tmp = 1;
//a switch without continue
puts ( "a switch without continue");
switch ( tmp ){
case 0:
puts ( "0");
case 1:
puts ( "1");
case 2:
puts ( "2");
case 3:
puts ( "3");
case 4:
puts ( "4");
case 5:
puts ( "5");
default:
puts ( "switch over\n");
}//end switch
//add continue before case 4
puts ( "add continue before case 4" );
switch ( tmp ){
case 0:
puts ( "0");
case 1:
puts ( "1");
case 2:
puts ( "2");
case 3:
puts ( "3");
continue;
case 4:
puts ( "4");
case 5:
puts ( "5");
default:
puts ( "switch over");
}//end switch
}
版权声明：本文内容由互联网用户自发贡献，该文观点仅代表作者本人。本站仅提供信息存储空间服务，不拥有所有权，不承担相关法律责任。如发现本站有涉嫌侵权/违法违规的内容， 请联系我们举报，一经查实，本站将立刻删除。
发布者：全栈程序员-站长，转载请注明出处：https://javaforall.net/138923.html原文链接：https://javaforall.net
