插入表达式以完成JAVA语句块时出现语法错误

Question

这是我的代码到目前为止，使一个程序，接受用户输入的1和100之间的数字，只有偶数。它还需要在输入N或N时结束，计算有效数字的总和并显示最大数字

我有一个错误，说语法错误插入“while（expression）”；要完成此代码图片上的块语句…：

"制度。出来println（“输入整数列表，按N或N将计算您的数字”）；'

任何帮助都将不胜感激

• 这是代码的开始：-

package week11;
import java.util.*;
public class repeatlist {

public static void main(String args[]){

        Scanner sc = new Scanner(System.in);
        int number = 0, Sum = 0; //variables
        char letter;
        char choice;

        //if (Number %2 ==0)
        {
        do

            System.out.println("Enter the list of whole numbers, pressing N or n will Calculate your numbers");
            number = sc.nextInt();
            letter = sc.next().charAt(0);


            {
                 while(letter != 'N' && letter != 'n' ); 
                    System.out.println("end of program");

                Sum = Sum + number;
                number = sc.nextInt(); 

            System.out.println("Sum is "+ Sum);
            System.out.print("Do you want to repeat the ");
            System.out.println("  Program ['Y' or 'N']");
            choice = sc.next().charAt(0);
            }
        }
}

}

Answer 1

这是为什么缩进很重要的一个很好的例子。当前循环本质上执行以下操作：

{
    do System.out.println("Enter the list of whole numbers, pressing N or n will Calculate your numbers");

    //Rest of your first code block 

    {
        while (letter != 'N' && letter != 'n'); //Does nothing

        //Your second code block
    }
}

大量不必要的括号和语句将导致代码无法按预期运行

也许你在找

do {
    //Your first code block
    //Your second code block
} while (letter != 'N' && letter != 'n' );

或

do {
    //Your first code block
} while (letter != 'N' && letter != 'n' );
//Your second code block

Answer 2

试试这个

    do {
        System.out.println("Enter the list of whole numbers, pressing N or n will Calculate your numbers");
        number = sc.nextInt();
        letter = sc.next().charAt(0);
    } 
    while (letter != 'N' && letter != 'n' ); 
    System.out.println("end of program");

    Sum = Sum + number;
    number = sc.nextInt(); 

    System.out.println("Sum is "+ Sum);
    System.out.print("Do you want to repeat the ");
    System.out.println("  Program ['Y' or 'N']");
    choice = sc.next().charAt(0);

尽量保持代码的良好格式，所有IDE都有一个选项可以为您设置格式。它会帮助你发现这些