1. 程式人生 > >break語句/Continue語句的新認識

break語句/Continue語句的新認識

break語句在java中的語法格式居然是:
'break' [label] ';'

在java的程式設計生涯中還沒看到break語句有這樣子出現的,有點的bat中的goto語句,不過bat是前面設定好label標籤,然後用goto語句跳轉到label標籤處重新執行一次。而break語句是指跳出該標籤指定的迴圈控制語句:

like:

outerwhile:
		while(true) {
			System.out.println("\n True/False: Blocks can be nested.\n");
			innerwhile1:
			while(true) {
				System.out.print("Enter t,f or any key to exit quit.");
				switch(System.in.read()) {
					case 't': System.out.println("You are correct.");
					          while (System.in.read() != '\n');
					          break innerwhile1;
					case 'f': System.out.println("You are wrong.");
							  while (System.in.read() != '\n');
							  break;
					default: break outerwhile;
				}
			}
			innerwhile2:
				while(true) {
					System.out.print("Enter t, f or any key to exit quit.");
					switch(System.in.read()) {
					case 't': System.out.println("You are wrong.");
							while(System.in.read() != '\n');
							break;
					case 'f': System.out.println("You are correct.");
							while(System.in.read() != '\n');
							break innerwhile2;
					default: break outerwhile;
					}
				}
		}
	
		System.out.println("Quiz has terminated");

 恰巧有一個Continue語句是可以跟goto語句是類似的如下:

couterFor:
			for(int i = 0; i < 10; i++) {
				for(int j = 0; j < 10; j++) {
					if((i - 3) == 0) {
						continue couterFor;
					}
					System.out.println((float)j/(i-3));
				}
			}

 以上的 程式碼中使用了標籤,這樣就可以避免被零除的情況。