java - 我的意图错误来自哪里？

Question

我的程序中的一切似乎都工作正常，但由于某种奇怪的原因，每当它到达您选择乘法或除法的输入部分时，它就会终止程序，就像它已经完成一样。

这有什么问题吗？

我尝试更改if(Choice.equals(Multiply))到“乘法”，其他也一样。

但运气不佳。

这是我的代码:

import java.util.Scanner;


public class APJAVAPROGRAM {


    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
    Scanner numberinput = new Scanner(System.in);
    Scanner stringinput = new Scanner(System.in);

    System.out.print("Input a numerator >>>");              // inputs first Numerator
    double Numerator = numberinput.nextDouble();

    System.out.print("Input a Denominator >>>");            // Inputs first denominator
    double Denominator = numberinput.nextDouble();


    System.out.print("Input a second numerator >>>");               //Inputs second Numerator
    double Numerator2 = numberinput.nextDouble();

    System.out.print("Input a second Denominator >>>");         // Inputs second denominator
    double Denominator2 = numberinput.nextDouble();


    System.out.println("Your entered fractions are " + Numerator + "/" + Denominator + "  and "+ Numerator2 + "/" + Denominator2);
    // Will print out the entered fractions

    System.out.println("What would you like to do with these?");          //asks user what should be done
    System.out.print("Multipy, Divide, Add, or Subtract >>>");
    String Choice = stringinput.nextLine();                               

    double Multiply = Numerator * Numerator2;                              
    double Multiply2 = Denominator * Denominator2;
    if(Choice.equals("Multiply"))
    {
    System.out.println(Multiply + "/" + Multiply2 + " Is your answer.");
    // If the input is multiply it will do as such
    }
    else    
    {
    double Divide = Numerator * Denominator2;
    double Divide2 = Numerator2 * Denominator;
    if(Choice.equals("Divide"))
    System.out.println(Divide + "/" + Divide2 + " Is your answer.");




    }
    }
}

Answer 1

.equals(Object obj) 区分大小写，如果您输入大写字母“乘”或“除”，它会正确运行。

使用.equalsIgnoreCase(Object obj)进行字符串与字符串的比较，忽略大小写考虑