我的循环有问题，我的错误是

Question

我的方向是编写一个代码（在java中），找到1,000到9,999（任何4位数字）之间的代码，满足四个条件：

1. 这四个数字都不一样
2. 千位数字是十位数字的3倍
3. 这个数字是奇数
4. 数字之和是27

这就是我目前所拥有的。我的//循环部分出现错误：

C4PP10.java:27: error: bad operand types for binary operator '&&'"

是出现的错误。

在我的脑海里，

顺便说一句，这是我的java课堂作业介绍。

public class C4PP10
{
    public static void main(String[] args)
    {
        //variables
        int first=1;
        int second=0;
        int third=0;
        int fourth=0;
        int total = first * 1000 + second * 100 + third * 10 + fourth;
        boolean fourDifferentDigits = false;
        boolean thousandsPlaceX3TensPlace = false;
        boolean odd = false;
        boolean sum = false;
        boolean correctAddress = false;

        //loop
        while (correctAddress = false)
        {
            fourth = fourth + 1;
            if (fourth == 10)
            {
                fourth = 0 && third = third + 1;
            }//end if
            if (third == 10)
            {
                third = 0 && second = second + 1;
            }//end if
            if (second == 10)
            {
                second = 0 && first = first + 1;
                total = first * 1000 + second * 100 + third * 10 + fourth;
            }//end if
        }//end loop


        //testing
        if ( first != second && first !=third && first !=fourth && second !=third &&                 second !=fourth && third != fourth )
        {
            fourDifferentDigits = true;
        }//end if

        if (first == third*3)
        {
            thousandsPlaceX3TensPlace = true;
        }//end if 

        if (fourth%2 != 0)
        {
            odd = true;
        }//end if

        if ( first + second + third + fourth == 27 )
        {
            sum = true;
        }//end if

        if (fourDifferentDigits=true && thousandsPlaceX3TensPlace=true && odd=true   && sum=true)
        {
            correctAddress = true;
        }//end if

        if (correctAddress = true)
        {
            System.out.println("The Riddler plans to strike " + total + " Pennsylvania     Avenue!");
        }

    }//end main
}//end class




Answer 1

如此多的格式错误，请确保在比较时，布尔语句使用=而不是=，并使用缩进以提高可读性。仅使用

public class C4PP10
{
    public static void main(String[] args)
    {
        //variables
        int first = 1, second = 0, third = 0, fourth = 0;
        int total = first * 1000 + second * 100 + third * 10 + fourth;
        boolean fourDifferentDigits = false, thousandsPlaceX3TensPlace = false;
        boolean odd = false, sum = false, correctAddress = false;

        while (correctAddress == false) // or while (!(correctAddress))
        {
            fourth = fourth + 1;
            if (fourth == 10)
            {
                fourth = 0;
                third = third + 1;
            }                
            if (third == 10)
            {
                third = 0
                second = second + 1;
            }
            if (second == 10)
            {
                second = 0 
                first = first + 1;
                total = first * 1000 + second * 100 + third * 10 + fourth;
            }
        }


        if (first != second && first != third && first != fourth && second !=third && second !=fourth && third != fourth)
        {
            fourDifferentDigits = true;
        }

        if (first == third * 3)
        {
            thousandsPlaceX3TensPlace = true;
        }

        if (fourth % 2 != 0)
        {
            odd = true;
        }

        if (first + second + third + fourth == 27)
        {
            sum = true;
        }

        if (fourDifferentDigits == true && thousandsPlaceX3TensPlace == true && odd == true && sum == true)
        {
            correctAddress = true;
        }

        if (correctAddress == true)
        {
            System.out.println("The Riddler plans to strike " + total + " Pennsylvania Avenue!");
        }

    }
}