Is it possible to ask the user to pick what class they'd like to run and then run that class?

I'm new to JAVA programming, and was wondering if it's possible/how to ask the user to input what class they'd like to run and then call/run that class?

Example:
I created two classes to solve the Towers of Hanoi given (supplied by user) n amount of disks. One class solves the puzzle recursively and the other class solves the puzzle iteratively. When I am asking the user for the number of disks they'd like to use, is it possible to ask them how they would like to solve the program whether it be recursively or iteratively and then call the class that they chose?

You can do this in a pretty straightforward manner using a common interface both solvers implement.

interface HanoiSolver {
    void solve(int n);
}

// iterative solver
class IterativeHanoi implements HanoiSolver {
    public void solve(int n) { ... }
}

// iterative solver
class RecursiveHanoi implements HanoiSolver {
    public void solve(int n) { ... }
}

public class MainClass {
    public static void main(String[] args) {
       // you can change this to read input however you like
       String userInput = args[0];
       Integer n = Integer.parseInt(args[1]);

       HanoiSolver solver;
       if (userInput.equals("recursive")) {
            solver = new RecursiveHanoi();
       } else {
            solver = new IterativeHanoi();
       }
       solver.solve(n);
    }
}



</details>



# 答案2
**得分**: 1

是的，这是可能的。

这个版本乍一看可能会更加复杂，但它更清楚地将各个部分分开。在实际应用中，接口和类通常会分别放在不同的文件中。另外，静态的 `chooseSolver` 方法可能会被移动到一个名为类似 `SolverFactory` 的单独类中。

```java
import java.util.Scanner;
import java.util.Set;

public class Main {

    interface Solver {
        void solveIt();
    }

    static class SuperSolver implements Solver {
        public void solveIt() {
            System.out.println("SuperSolver总是解决任何问题");
        }
    }

    static class FastSolver implements Solver {
        public void solveIt() {
            System.out.println("没有人能击败FastSolver");
        }
    }
    
    public static void main(String[] args) {
        String in = askUserForOption();
        Solver s = chooseSolver(in);
        s.solveIt();
    }

    private static String askUserForOption() {
        String in;
        Set<String> validOptions = Set.of("A", "B");        
        try (Scanner sc = new Scanner(System.in)) {

            do {
                System.out.print("输入A或B：");
                in = sc.nextLine();
            } while (!validOptions.contains(in));
        }
        return in;
    }

    private static Solver chooseSolver(String in) {
        switch (in) {
        case "A":
            return new SuperSolver();
        case "B":
            return new FastSolver();
        default:
            throw new IllegalArgumentException("出现严重错误 - 给出了无效的选项");
        }
    }
}

import java.util.Scanner;
import java.util.Set;
public class Main {
interface Solver {
void solveIt();
}
static class SuperSolver implements Solver {
public void solveIt() {
System.out.println("SuperSolver always solves anything");
}
}
static class FastSolver implements Solver {
public void solveIt() {
System.out.println("Noone beats the FastSolver");
}
}
public static void main(String[] args) {
String in = askUserForOption();
Solver s = chooseSolver(in);
s.solveIt();
}
private static String askUserForOption() {
String in;
Set<String> validOptions = Set.of("A", "B");		
try (Scanner sc = new Scanner(System.in)) {
do {
System.out.print("Enter A or B: ");
in = sc.nextLine();
} while (!validOptions.contains(in));
}
return in;
}
private static Solver chooseSolver(String in) {
switch (in) {
case "A":
return new SuperSolver();
case "B":
return new FastSolver();
default:
throw new IllegalArgumentException("something went terribly wrong - an invalid option was given");
}
}
}

答案3

得分: 0

根据代码是在内部使用还是作为库包使用而定。
在内部，您可以使用接口，然后分离出具体的实现。

在库中，您可以再次让用户调用接口方法，根据条件编写该接口的实现。

或者，如果您希望用户在运行时确定要使用的算法，则可以使用反射来决定创建哪个类的对象。