Do-While循环打印文本以提示用户输入sentinel值，然后在接收输入之前重新启动

Question

    import java.util.Scanner;

public class DonutSign {
    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);
            //initiate all variables
        boolean ans = false;
        double r = 0;
        double sideA = 0;
        double sideB = 0;
        double angle = 0;
        String text = "INTIAL";
        
        double circleArea = 0;
        double parArea = 0;
        double finalArea = 0;
        double sizePrice = 0;
        double textPrice = 0;
        double finalPrice = 0;
        String response = "quit";
    
            //do-while price calculation
        do{
                //have all of the variables entered
            System.out.println("Enter the radius of the circles:");
            r = input.nextDouble();
            System.out.println("Enter the first side of the parallelogram:");
            sideA = input.nextDouble();
            System.out.println("Enter the second side of the parallelogram:");
            sideB = input.nextDouble();
            System.out.println("Enter the angle of the parallelogram:");
            angle = input.nextDouble();
            System.out.println("Enter the string you would like on your sign:");
            text = input.next();
            
                //calculate area of the circles
            circleArea = Math.PI * Math.pow(r, 2);
                //calculate area of parallelogram
            parArea = sideA * sideB * (Math.sin(Math.toRadians(angle)));
                //add surface area values together and calculate price
            finalArea = circleArea + parArea;
            sizePrice = finalArea * 2.95;
                //calculate price of text and add values
            textPrice = ((text.length() + 1)    * 1.45);
            finalPrice = textPrice + sizePrice;
            System.out.print("$");
            System.out.printf("%.2f", finalPrice);
            System.out.println();
            
            
                //If-else to exit the loop
            System.out.println("Would you like to create another sign? Enter quit to exit.");
            response = input.nextLine();
            if(response == "quit"){
                ans = true;
            }
            else{
                ans = false;
            }
        } while (ans != true);      
    }
}

Answer 1

这里有一个很好的答案：

Java扫描器不等待用户输入

问题是nextInt（）不使用'\n'，所以下一次调用nextLine（）会使用它，然后它会等待读取Y的输入。