为什么当 charat 和 String.value 的比较是相同的值时,它们不返回 true?



这是我的程序:

import java.util.Scanner;
public class Lottery
{
public static void main(String[] args)
{
    //declare and initialized variables and objects
    Scanner input = new Scanner(System.in);
    String lotteryNum = "";
    String userGuess = "";
    //Generate a 3-digit "lottery" number composed of random numbers
    int num1 = (int)(Math.random()*10);
    int num2 = (int)(Math.random()*10);
    int num3 = (int)(Math.random()*10);
    //Simulate a lottery by drawing one number at a time and 
    //concatenating it to the string
    String c1 = String.valueOf(num1);
    String c2 = String.valueOf(num2);
    String c3 = String.valueOf(num3);
    lotteryNum = (c1+c2+c3);
    //Identify the repeated steps and use a for loop structure
    //Input: Ask user to guess 3 digit number
    System.out.println("WINNER:"+lotteryNum+" Please enter your three numbers (e.g. 123): ");
    userGuess = input.next();
    System.out.println(c1.equals(userGuess.charAt(0)));
    System.out.println(userGuess.charAt(0) +"   " + userGuess.charAt(1) + "     " + userGuess.charAt(2) + "n" + c1 + "t"+c2+"t"+c3);;
    if (c1.equals(userGuess.charAt(0)) && c2.equals(userGuess.charAt(1)))
        System.out.println("Winner: "+ lotteryNum+"nCongratulations, the front pair matched.");
    else if (c2.equals(userGuess.charAt(1)) && c3.equals(userGuess.charAt(2)))
        System.out.println("Winner: "+ lotteryNum+"nCongratulations, the end pair matched.");
    else if (c1.equals(userGuess.charAt(0)) && c2.equals(userGuess.charAt(1)) && c3.equals(userGuess.charAt(2)))
        System.out.println("Winner: "+ lotteryNum+"nCongratulations, both pairs matched.");
    else 
                System.out.println("Winner: "+ lotteryNum+"nSorry, no matches. You only had n one chance out of 100 to win anyay.");
} //end main
}//end class Lottery

出于某种原因,具有以下逻辑的线路:

System.out.println(c1.equals(userGuess.charAt(0)));

具体来说,返回false,即使用户输入了相同的值,即String.valueOf(num1)userGuess.charAt(0)是同一个值,我甚至认为它们都是字符串,但它仍然返回false。为什么?

因为String不是char
if (c1.equals(String.valueOf(userGuess.charAt(0))) 
        && c2.equals(String.valueOf(userGuess.charAt(1))))

较短的

if (c1.charAt(0) == userGuess.charAt(0) && c2.charAt(0) == userGuess.charAt(1))

userGuess.charAt(0)返回char

c1 is String

可以按照建议使用CCD_ 8。

您也可以使用Character.toString(char);

System.out.println(c1.equals(Character.toString(userGuess.charAt(0))));

我们需要转换String to charchar to String,然后比较

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