Java中for循环中执行顺序问题及break, continue标签用法
public class labeledfor { static test monitor = new test(); public static void main(string[] args) { int i = 0; outer: // can't have statements here for(; true ;) { // infinite loop inner: // can't have statements here for(; i < 10; i++) { system.out.println("i = " + i); if(i == 2) { system.out.println("continue"); continue; } if(i == 3) { system.out.println("break"); i++; // otherwise i never // gets incremented. break; } if(i == 7) { system.out.println("continue outer"); i++; // otherwise i never // gets incremented. continue outer; } if(i == 8) { system.out.println("break outer"); break outer; } for(int k = 0; k < 5; k++) { if(k == 3) { system.out.println("continue inner"); continue inner; }?结果:
"i = 0",
"continue inner",
"i = 1",
"continue inner",
"i = 2",
"continue",
"i = 3",
"break",
"i = 4",
"continue inner",
"i = 5",
"continue inner",
"i = 6",
"continue inner",
"i = 7",
"continue outer",
"i = 8",
"break outer"
总结：
? (1):一般的continue会退回最内层循环的开头（顶部），并继续执行。
? (2):带标签的continue会到达标签的位置，并重新进入紧接在那个标签后面的循环。
? (3):一般的break会中断并跳出当前的循环。
? (4):带标签的break会中断并跳出标签所指的循环。
要记住的重点是：在Java里面需要使用标签的唯一理由是因为有循环嵌套的存在，而且像从多层嵌套中break或continue。