Java平方数

Question

我不明白为什么输出是25，因为我的错误理解，显然，我认为它是20，因为：第一个循环将是：i = 2; x = 5，并且自i <= m之后将有4个循环，因此5 x 4 = 20。我知道我错了，但不知道在哪里

public class num {
    public static void main(String[] args) {

       int m, x, i;

        x = 0;
        i = 1;
        m = 5;

        while (i<= m){
            x = x + m;
            i = i + 1;

        }
        System.out.println(x);
    }
}

Answer 1

如果遇到这种情况，请尝试调试和打印。大多数时候，你会发现你的answqer：

public class num {
    public static void main(String[] args) {
        int m, x, i;

        x = 0;
        i = 1;
        m = 5;

        System.out.println("Initial : x = " + x + " and i = " + i);

        while (i <= m) {
            x = x + m;
            i = i + 1;
            System.out.println("x = " + x + " and i = " + i);
        }
        System.out.println(x);
    }
}

输出：

Initial : x = 0 and i = 1
x = 5 and i = 2
x = 10 and i = 3
x = 15 and i = 4
x = 20 and i = 5
x = 25 and i = 6
25

Answer 2

让我们试着试一试：

x=0;i=1;m=5
while (1<=5) ? yes, so x=0+5; i=2,
while (2<=5) ? yes, so x=5+5; i=3,
while (3<=5) ? yes, so x=10+5; i=4,
while (4<=5) ? yes, so x=15+5; i=5,
while (5<=5) ? yes, so x=20+5; i=6,
while (6<=5) ? no, so exit from loop

因此结果是：x=25