因为
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)
与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?
String
不是char
。
if (c1.equals(String.valueOf(userGuess.charAt(0)))
&& c2.equals(String.valueOf(userGuess.charAt(1))))
或较短的
if (c1.charAt(0) == userGuess.charAt(0) && c2.charAt(0) == userGuess.charAt(1))
userGuess.charAt(0)
返回char
而
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 char
或char to String
,然后比较