Why is this happening?

Question

Java

package rhymeCounter;
import java.util.*;
import java.io.*;
public class rhymeCounter {
Scanner myConsoleScanner = new Scanner(System.in);
PrintWriter myPrinter = new PrintWriter(System.out);
public static void rhyme() throws IOException {
String a1 = "Twenty-one, Thirty-one, Forty-one, Fifty-one";
String a2 = "Twenty-two, Thirty-two, Forty-two, Fifty-two";
for(int i = 1; i <= 100; i++) {
switch(i) {
case 1:
String j = a1;
break;
case 2:
j = a2; break;
}
System.out.println("The number " + i + "has these rhymes: " + j );
}
}
}
Gives an error : " j cannot be resolved to a variable "
Where did I go wrong ? What's wrong ?

Answer 1

The problem is in the scope of the variable j. The point is that your variable is only visible in case 1 and nowhere else. Therefore, the compiler swears that it is impossible to assign a value. Declare j at the beginning of the loop, or make it static, and you'll be fine. For example like this

import java.io.IOException;
import java.io.PrintWriter;
import java.util.Scanner;

public class Apply {

    Scanner myConsoleScanner = new Scanner (System.in);
    PrintWriter myPrinter = new PrintWriter (System.out);
    static String j;

    public static void main(String[] args) {
        try{
            Apply.rhyme ();
        }
        catch (IOException ex){
            ex.printStackTrace ();
        }
    }

    public static void rhyme() throws IOException {
        String a1 = "Двадцать один, Тридцать один, Сорок один, Пятьдесят один";
        String a2 = "Двадцать два, Тридцать два, Сорок два, Пятьдесят два";

        for(int i = 1; i <= 100; i++) {
            switch(i) {
                case 1:
                    j = a1;
                    break;
                case 2:
                    j = a2; break;
            }
            System.out.println("У числа " + i + "эти рифмы : " + j );
        }
    }
}

Answer 2

j inside case. must be declared before switch

Answer 3

Because j is defined in the case 1 block, and is only available there. And you are trying to use it in other scopes. Move the declaration before the switch, and leave only the assignment in case 1. These are elementary things that are covered in the first 2-3 chapters of any book on Java.