Question

while（var！= var） System.out.println（“loop ..”）;

执行它.. 如何声明..var

Answer 1

假设这是家庭作业，我会给你一个提示，而不是答案。您需要像这样定义var：

double var = // time for you to understand floating point

编辑：为了使这个答案更有用，这里是Wikipedia's entry on special floating-point values。

Answer 2

public static void main(String[] args) {
    double var = Double.NaN;
    System.out.println("var : " + var);
    while (var != var) {
        System.out.println(" I am inside loop now! ");
    }

}

Answer 3

double var = Double.NaN

Answer 4

此外，以下将导致无限循环，而不是无限循环;但是如果在主循环中有更多东西在进行，那么[我认为]这可能会有效地无限;我认为值得发布，因为这是现实生活中App Server可能发生的事情：

public class Puzzle extends Thread {
static boolean keepRunning=true;
static int var=0;



public void run() {

while (keepRunning) {
        var++;
}   

}


public static void main(String[] args) {
    Puzzle p=new Puzzle();
    p.setPriority(Thread.MAX_PRIORITY);
    Thread.currentThread().setPriority(Thread.MIN_PRIORITY);
    p.start();
    System.out.println("Background Thread started");
    try { Thread.sleep(1000); } catch(Exception e) { ; } // Dirty hack to give the background thread chance to start :)
    while (var != var) {
        System.out.println(" I am inside loop now! ");
    }

    keepRunning=false; // we escaped from the loop, switch off the background thread.
}

}

而（var！= var）

4 个答案: