JAVA 花括号

问题描述

在我的花括号上收到一个语法错误，但无论我关闭多少个它仍然会出现错误。想不通感谢您对此的任何建议，我不知所措。我尝试添加更多并删除更多。我计算了需要关闭的次数，但仍然出现错误。

import java.util.Scanner;

public class Paint1 {

    public static void main(String[] args) {
        Scanner scnr = new Scanner(system.in);
        double wallHeight = 0.0;
        double wallWidth = 0.0;
        double wallArea = 0.0;
        double gallonsPaintNeeded = 0.0;
        
        final double squareFeetPergallons = 350.0;
        
        // Implement a do-while loop to ensure input is valid
        // Prompt user to input wall's height
        do {
            
        System.out.println("Enter wall height (feet): ");
        wallHeight = scnr.nextDouble();
            while (!scnr.hasNextInt()) {
                System.out.printf("\"%s\" is not a valid number.\n");
                System.out.println("Please enter wall height in feet: ");
            } while (wallHeight < 0) {
            
        
        // Implement a do-while loop to ensure input is valid
        // Prompt user to input wall's width
            do {
        System.out.println("Enter wall width (feet): ");
        wallWidth = scnr.nextDouble(); // changed wallHeight to wallWidth
        while (!scnr.hasNextDouble()) {
            System.out.printf("\"%s\" is not a valid number.\n");
            System.out.println("Please enter wall width in feet: ");
        } while (wallWidth < 0) {
        
        
            
        
        // Calculate and output wall area
        wallArea = wallHeight * wallWidth;
        System.out.println("Wall area: " + wallArea + " square feet"); // added variable

        // Calculate and output the amount of paint (in gallons) needed to paint the wall
        gallonsPaintNeeded = wallArea/squareFeetPergallons;
        System.out.println("Paint needed: " + gallonsPaintNeeded + " gallons"); // changed variable to correct case
        
            }
}

解决方法

您尝试实现 do while 循环，但出现错误。

你必须让它看起来像那样

do {
//something
//something
}while(condition);

您可以在此处阅读有关此循环的更多信息：https://www.javatpoint.com/java-do-while-loop

您似乎在 } while (wallWidth < 0) { 行中有一个额外的花括号。你有没有试过删除它？大括号没问题，但行尾的大括号可能会给您带来问题。

你的 do while 循环有问题。

第 19 行和第 29 行上的 do 永远不会关闭，并且最后缺少 while 子句。除此之外，您还缺少 4 个花括号。

public class Paint1 {

    public static void main(String[] args) {
        //...
        do {
            //...
            while (!scnr.hasNextInt()) {
                //..
            }
            while (wallHeight < 0) {
                // ..
                do {
                    // ..
                    while (!scnr.hasNextDouble()) {
                    }
                    while (wallWidth < 0) {
                    }
                } while (true); // Should have a clause,or will be an infinite loop
            }
        } while (true); // Should have a clause,or will be an infinite loop
    }
}

braces java java