为什么仅仅因为 while 循环中语句的位置发生变化，输出就会发生如此巨大的变化？

Question

嗯，在试图理解 while 循环的全部概念时，我遇到了这个..

public static void main (String[] args) {

    int x = 1;
    System.out.println("Before the loop");

    while(x < 4) {
        x = x + 1;
        System.out.println("In the loop");
        System.out.println("Value of loop x is " + x);
    }

    System.out.println("This is after the loop");

}

这里的输出是

Before the loop
In the loop
Value of loop x is 2
In the loop
Value of loop x is 3
In the loop
Value of loop x is 4
This is after the loop

当我这样改变语句的位置时，

    public static void main (String[] args) {

    int x = 1;
    System.out.println("Before the loop");

    while(x < 4) {
        System.out.println("In the loop");
        System.out.println("Value of loop x is " + x);
        x = x + 1;
    }

    System.out.println("This is after the loop");

}

输出是，

Before the loop
In the loop
Value of loop x is 1
In the loop
Value of loop x is 2
In the loop
Value of loop x is 3
This is after the loop

请向我解释为什么仅通过更改该语句的位置，输出就会发生如此巨大的变化。

如有任何帮助，我们将不胜感激...我是一个志存高远的学习者 ;)

Answer 1

你基本上是这样的：

x = 1
x = x + 1 // X=2
print x   // X=2
--> and then to next loop

和

x = 1
print x    // X=1 
x = x + 1  // X=2
--> and then to next loop

所以，这真的不是很大的变化，它是值的 +1，因为你在打印之前和打印之后进行了比较

为什么仅仅因为 while 循环中语句的位置发生变化，输出就会发生如此巨大的变化？

Why does the output change so drastically just because of the change in location of the statement in the while loop?

java

conditional

loops

while-loop

statements