Thread: Switch statements to initialize variable due to multiple outcomes?

After this problem is fixed, my math game will run. The answer variable is supposed to be equal to the cases in the second switch statement by random but I get errors whenever I try to initialize it this way. I have been writing this program for almost 5 days now and it is finally wrapping up. Does anyone know why I can't map the answer variable to the second switch statement the way I want to?

package pkgnew;
 
import java.util.Scanner;
import java.util.Random;
 
public class New {
 
    public static void main(String args[]) {
 
        //Declare and construct variables 
        Random randomnum = new Random();
        int fnum, snum, answer;
        int mathnumber = randomnum.nextInt(20);
        int newnumber = randomnum.nextInt(20);
 
        //Declare and construct variables of math problem
        fnum = mathnumber;
        snum = newnumber;
 
        //Declare random operator variable
        String[] operators = {"+" , "-", "*", "/" };
        int randomIndex = randomnum.nextInt(3);
        String symbol = operators[randomIndex];
 
        //Switch statement for random operator and question display
        switch (symbol) {
            case "+": 
                System.out.println(fnum + "+" + snum);
                break;
            case "-":
                System.out.println(fnum + "-" + snum);
                break;
            case "*":
                System.out.println(fnum + "*" + snum);
                break;
            case "/":
                System.out.println(fnum + "/" + snum);
                break;
        }
 
        //Declare random answer variable
        String[] solutions = {fnum + "+"+ snum, fnum + "-" + snum, 
        fnum + "*" + snum, fnum + "/" + snum };
        int randomCase = randomnum.nextInt(3);
        String userInput = solutions[randomCase];
 
        //Switch statement to map answer to question display
        switch (userInput) {
        case "fnum + \"+\"+ snum":
            answer = fnum + snum;
            break;
        case "fnum + \"-\" + snum":
            answer = fnum - snum;
            break;
        case "fnum + \"*\" + snum":
            answer = fnum * snum;
            break;
        case "fnum + \"/\" + snum":
            answer = fnum / snum;
            break;
        }
 
        //User input
        Scanner serena = new Scanner(System.in);
        int userAnswer = serena.nextInt();
 
        //If user input = answer display "correct"
        if (userAnswer == answer) {
        System.out.println("Correct!");
 
        //If user input does not = answer display "wrong" and correct answer
        } else {
        System.out.print("Wrong! The correct answer is: ");
        System.out.print(answer);
        }
 
}
}

First of all, the error message would probably be of much help.
Second, if I had to guess (which I have, because you did not provide us with the error message) I would say that there are certain cases in which the variable will never be initialized which is forbidden in java.

Well if it is trouble to you,do not respond. It will only cause more trouble for you.

Originally Posted by kunimaro15689

Well if it is trouble to you,do not respond. It will only cause more trouble for you.

Why the attitude? Let's say it's simply a misunderstanding due to language differences.

From that perspective, it's common courtesy and widely advised throughout the forum to post the error message(s) you want help with. Copy and paste them into a post from exactly as they appear at your end. If the errors are logical rather than compiler or run time, then describe the errors you want help with as best you can.

Guessing what you want help with is typically unproductive.

I made a math game with the variable "answer" being the actual answer. But the actual answer is dependent upon the math question. Can I use a switch statement to initialize the variable and map it to the outcomes of the original switch statement? It is possible to map switch statements to each other. I have done it. The question is; is it possible to initialize a variable via switch statement due to multiple outcomes?

Please stop posting duplicate or nearly duplicate threads. Hang with one thread and those trying to help you.

Threads merged.

I am making a math game that asks the user elementary questions.I have no errors. The answer variable was to be initialized in my second switch statement with the value 0 being default for the variable. However, when I run the program, I always get the answer 0. The answer variable has to be initialized but i need it to be so with the solution of the equations in the second switch statement. How do I initialize a variable that has multiple possibilities?

package pkgnew;
 
import java.util.Scanner;
import java.util.Random;
 
public class New {
 
    public static void main(String args[]) {
 
        //Declare and construct variables 
        Random randomnum = new Random();
        int fnum, snum, answer;
        int mathnumber = randomnum.nextInt(20);
        int newnumber = randomnum.nextInt(20);
 
        //Declare and construct variables of math problem
        fnum = mathnumber;
        snum = newnumber;
 
        //Declare random operator variable
        String[] operators = {"+" , "-", "*", "/" };
        int randomIndex = randomnum.nextInt(3);
        String symbol = operators[randomIndex];
 
        //Switch statement for random operator and question display
        switch (symbol) {
            case "+": 
                System.out.println(fnum + "+" + snum);
                break;
            case "-":
                System.out.println(fnum + "-" + snum);
                break;
            case "*":
                System.out.println(fnum + "*" + snum);
                break;
            case "/":
                System.out.println(fnum + "/" + snum);
                break;
        }
 
        //Declare answer variable
        String[] solutions = {fnum + "+"+ snum, fnum + "-" + snum, 
        fnum + "*" + snum, fnum + "/" + snum };
 
        //Switch statement to map answer to question display
        switch (solutions[3]) {
        case "fnum + \"+\" + snum":
            answer = fnum+snum;
            break;
        case "fnum + \"-\" + snum":
            answer = fnum-snum;
            break;
        case "fnum + \"*\" + snum":
            answer = fnum*snum;
            break;
        case "fnum + \"/\" + snum":
            answer = fnum/snum;
            break;
        default: answer = 0;  
        }
 
        //User input
        Scanner serena = new Scanner(System.in);
        int userAnswer = serena.nextInt();
 
        //If user input = answer display "correct"
        if (userAnswer == answer) {
        System.out.println("Correct!");
 
        //If user input does not = answer display "wrong" and correct answer
        } else {
        System.out.print("Wrong! The correct answer is: "+answer);
        }
 
}
}

Please stop posting duplicate threads. This is the second time you've been asked. Future infractions may require additional action.

The threads you merged were the only two.

How do I initialize a variable that has multiple possibilities?

If you know the value of the variable will be properly set later - in the switch statement, for example - then initialize the variable to zero or perhaps some other value (-9999999.9) that will indicate that an error has occurred if the switch statement assignment fails for some reason.

Thanks, Greg. I have defaulted the answer to 0 and that is always the result when I run the game. This leads me to believe that my second switch statement is a bit wrong. In the first I use random operators to display all of the possibilities of the equations I wish to display. The second switch is based off of the results of the first switch. For example: if the results of the first switch says to display fnum + snum randomly, the second switch is to find that and calculate the answer to compare the user's answer to it's own. So the results of the first switch are the cases in the second. If the results and the cases match then I should have the answer variable problem solved. I am just not sure how to find the random results of the first switch with the second