Java 用户输入和If-then和else

我试图创建一个简单的

20个问题的游戏

，通过用户输入来获取用户输入，我对java编程相当陌生

我已经为我的问题设置了所有的字符串，我想问用户是否想玩。我试图用用户输入设置一个

if-then

语句，数字

1

为

Yes

，数字

2

为

No

我该怎么设置呢？我尝试了我的

if（in.nextInt（）=a）

语句，但我知道这是不对的。我知道我需要引用以前的用户输入，但是我该怎么做呢？提前谢谢你的帮助

import java.util.*;

public class twentyq {

    public static void main(String[] args) {
        // TODO Auto-generated method stub

        Scanner in = new Scanner(System.in);

        int a = 1;
        int b = 2;

        // all the Strings needed for Questions[represented by the Q(1-20) variable] and their Answers[represented by the AQ(1-20) variable] 
        String Q1;
        String Q2;
        String Q3;
        String Q4;
        String Q5;
        String Q6;
        String Q7;
        String Q8;
        String Q9;
        String Q10;
        String Q11;
        String Q12;
        String Q13;
        String Q14;
        String Q15;
        String Q16;
        String Q17;
        String Q18;
        String Q19;
        String Q20;

        String AQ1;
        String AQ2;
        String AQ3;
        String AQ4;
        String AQ5;
        String AQ6;
        String AQ7;
        String AQ8;
        String AQ9;
        String AQ10;
        String AQ11;
        String AQ12;
        String AQ13;
        String AQ14;
        String AQ15;
        String AQ16;
        String AQ17;
        String AQ18;
        String AQ19;
        String AQ20;


        // The questions and their answers in numerical order question first then answer immediately following.
        Q1 = "Where would you find the Sea of Tranquility?";
        AQ1 = "The Moon.";

        Q2 = "What is the Capital of Spain";
        AQ2 = "Madrid.";

        Q3 = "What is the painting, La Gioconda, more usually known as?";
        AQ3 = "The Mona Lisa.";

        Q4 = "Which chess piece can only move diagonally?";
        AQ4 = "A Bishop.";

        Q5 = "What is the oldest surviving printed book in the world?";
        AQ5 = "The Diamond Sutra, dated at 868 AD.";

        Q6 = "Costing around $2,600 per pound, and made only to order by Knipschildt, what is the name of this chocolate truffle?";
        AQ6 = "Chocopologie";

        Q7 = "Who invented TV?";
        AQ7 = "George Carey, a Boston civil servant, first thought up television in 1876. John Logie Baird is often quoted as its inventor but his ideas didn't come along until the 1920's.";

        Q8 = "What is allspice alternatively known as?";
        AQ8 = "Pimento.";

        Q9 = "In publishing, what does POD mean?";
        AQ9 = "Print on demand.";

        Q10 = "What is John Leach famous for making?";
        AQ10 = "Pottery.";

        Q11 = "When was the euro introduced as legal currency on the world market?";
        AQ11 = "1st January, 1999.";

        Q12 = "How many valves does a trumpet have?";
        AQ12 = "3.";

        Q13 = "Which kind of bulbs were once exchanged as a form of currency?";
        AQ13 = "Tulips.";

        Q14 = "Name the director of the Lord of the Rings trilogy.";    
        AQ14 = "Peter Jackson.";

        Q15 = "Name the largest fresh water lake in the world?";
        AQ15 = "Lake Superior.";

        Q16 = "Name the seventh planet from the sun.";
        AQ16 = "Uranus.";

        Q17 = "Which country is Prague in?";
        AQ17 = "Czech Republic.";

        Q18 = "What is the oldest film ever made, and when was it made?";
        AQ18 = "Roundhay Garden Scene, made in 1888.";

        Q19 = "Name the three primary colors.";
        AQ19 = "Red, yellow and blue.";

        Q20 = "How old is the world's oldest dictionary?";
        AQ20 = "Cuniform tablets with bilingual Sumerian-Akkadian word-lists have been dated to 2300 BC.";

        System.out.println("Welcome To KCH39's 20 Questions!");
        System.out.println("Would you like to play? If yes, press 1 and enter. If not, press 2 and enter.");

        in.nextInt();

        if (in.nextInt() = a){
            system.out.println(Q1);


        }


    }

}

---

您正在使用赋值运算符而不是等于运算符：

if (in.nextInt() == a){
    system.out.println(Q1);
}

---

在当前代码中，将

（In.nextInt（）=a）

更改为

（In.nextInt（）=a）

=

是赋值运算符，

=

（相等运算符）用于比较

使用等于运算符（=），而不是赋值（=）

另一个选项是先将该值分配给另一个int，然后进行检查

int b == in.nextInt()

if(b==a)

---

您的程序抛出以下编译器错误。为了避免比较，您正在尝试将“a”的值赋给in.nextInt（），这是不可能的

twentyq.java:120: error: unexpected type
    if (in.nextInt() = a){
                  ^
  required: variable
  found:    value
1 error

因此，它必须固定如下（即使用双等于）：

---

感谢您的编辑：）。我不知道我把事情搞砸了。你可能想好好读一读。更简单的可能是在课堂上提出一个“问题”。然后在这个“q”和“a”中有两个字符串，它们包含问题和答案。然后将这些问题添加到数组问题[20]。这将大大减少重复。现在，当我按1并按enter键时，它不会打印下一行。我如何修复它？将system.out.println（）更改为system.out.println（）？

int b == in.nextInt()

if(b==a)

twentyq.java:120: error: unexpected type
    if (in.nextInt() = a){
                  ^
  required: variable
  found:    value
1 error

    if (in.nextInt() == a){
        System.out.println(Q1);
    }