如何在java中循环回程序的开头

Question

I know this is a simple Java concept but I am just now learning how to code in it. I was wondering if anyone could help me write a statement so that after the conversion is printed, another statement is printed saying "Type 'redo' to go to the beginning of the program." Which then would allow them to make another choice. Here is the code I have:

package convertorPackage;

import java.util.Scanner;

public class SimpleConvertor {

    public static void main(String[] args) {

        Scanner input = new Scanner(System.in);

        double length = 0.39370;

        System.out.println("Welcome to simple convertor.");
        System.out.println("Pick an option and its corresponding letter to select.");
        System.out.println("Farenheight to Celsius: f");
        System.out.println("Celsius to Farenheight: c");
        System.out.println("Inches to Centimeters: i");
        System.out.println("Centimeters to Inches: ce");
        System.out.println("");
        System.out.println("Make your choice: ");
        String choice = input.nextLine();

        if ( choice.equals("f") ) {

            float farenheight;     

            System.out.println("Enter temperatue in Fahrenheit: ");
            farenheight = input.nextInt();

            farenheight = ((farenheight - 32)*5)/9;

            System.out.println("Temperatue in Celsius = " + farenheight);

        } else if ( choice.equals("c") ) {

            float celsius;     

            System.out.println("Enter temperatue in Celsius: ");
            celsius = input.nextInt();

            celsius = ((celsius)*18/10)+32;

            System.out.println("Temperatue in Farenheight = " + celsius);

        } else if ( choice.equals("i") ) {

            double inches;     

            System.out.println("Enter length in Inches: ");
            inches = input.nextInt();

            inches = (inches/length);

            System.out.println("Length in Centimeters = " + inches);
        } else if ( choice.equals("ce") ) {

            double centimeters;     

            System.out.println("Enter length in Centimeters: ");
            centimeters = input.nextInt();

            centimeters = (centimeters*length);

            System.out.println("Length in Inches is = " + length);
        }
    }
}

Answer 1

package convertorPackage;

import java.util.Scanner;

public class SimpleConvertor {

    public static void main(String[] args) {

        Scanner input = new Scanner(System.in);
        while (true) {
            //Conversion stuff here
            String response = input.nextLine();
            if (!response.equals("redo")) {
                break;
            }
        }

    }
}

Answer 2

Wrap your code which need to loop by a while loop.

public class SimpleConvertor {

    public static void main(String[] args) {


        Scanner input = new Scanner(System.in);

        double length = 0.39370;

        System.out.println("Welcome to simple convertor.");

        boolean cont = true;
        while (cont) {
            System.out.println("Pick an option and its corresponding letter to select.");
            System.out.println("Farenheight to Celsius: f");
            System.out.println("Celsius to Farenheight: c");
            System.out.println("Inches to Centimeters: i");
            System.out.println("Centimeters to Inches: ce");
            System.out.println("");
            System.out.println("Make your choice: ");
            String choice = input.nextLine();

            if ( choice.equals("f") ) {

                float farenheight;

                System.out.println("Enter temperatue in Fahrenheit: ");
                farenheight = input.nextInt();

                farenheight = ((farenheight - 32)*5)/9;

                System.out.println("Temperatue in Celsius = " + farenheight);

            } else if ( choice.equals("c") ) {

                float celsius;

                System.out.println("Enter temperatue in Celsius: ");
                celsius = input.nextInt();

                celsius = ((celsius)*18/10)+32;

                System.out.println("Temperatue in Farenheight = " + celsius);

            } else if ( choice.equals("i") ) {

                double inches;

                System.out.println("Enter length in Inches: ");
                inches = input.nextInt();

                inches = (inches/length);

                System.out.println("Length in Centimeters = " + inches);
            } else if ( choice.equals("ce") ) {

                double centimeters;

                System.out.println("Enter length in Centimeters: ");
                centimeters = input.nextInt();

                centimeters = (centimeters*length);

                System.out.println("Length in Inches is = " + length);
            }
            choice = input.nextLine();
            if ("redo".equals(choice)) {
                cont = true;
            } else {
                cont = false;
            }
        }
    }
}