java - 在java中使用循环进行乘法显示不正确的答案

Question

我尝试分别使用 for 、 while 和 do-while 循环来计算 5*10*15*...50 。当我运行代码时，它显示错误答案，等于 0。我无法找出代码中的问题。有人可以帮我看一下吗？？非常感谢~~下面是我的代码:

public class Main {

    public static void main(String[] args) {


        ForMethod show1 = new ForMethod();  
        show1.computeForLoop();
        System.out.println();

        DWMethod show2 = new DWMethod();
        show2.computeDWLoop();
        System.out.println();

        WhileMethod show3 = new WhileMethod();
        show3.computeWhileLoop();

    }

}


// For Loop
public class ForMethod {

    long mul;

    public void computeForLoop(){

        System.out.println("Compute using For Loop : ");
        for(int x = 1; x <= 10 ; x++){

            if ( x < 10){

                System.out.print(x*5 + " x ");

            } else { System.out.print(x*5);}

            mul *= x*5;
        }

        System.out.println("\nThe Product of Number = " + mul);

    }
}


// While Loop Method
public class WhileMethod {

    int x = 1 ;
    long mul;

    public void computeWhileLoop(){

                System.out.println("Compute using While Loop : ");

        while(x < 10){

            System.out.print(x*5 + " x ");
            x++;


            if (x == 10){

                System.out.print(x*5);
            }

            mul *= (x*5);
        }

        System.out.println();
        System.out.println("The Product of Number = " + mul);
    }


}


// Do-While Loop Method
public class DWMethod {

    int x = 1;
    long mul;

    public void computeDWLoop(){

            System.out.println("Compute using Do-While Loop : ");

        do{

            if (x < 10 ){

                System.out.print(x*5 + " x ");

            } else

                if (x == 10){

                    System.out.print(x*5);
                }

            mul *= x;
            x++;

        } while (x <= 10);


        System.out.println();
        System.out.println("The Product of Number = " + mul);

    }
}

Answer 1

问题是您的 mul 字段已初始化为零。这意味着您总是乘以零。