Thread: Random math operators and asking ten questions with a loop?

So my little math game is working so far. I can only do addition though. I know how to fix it if I can find out how to generate random math operators. After that I want to use a loop (or a better technique) to ask ten different math questions before the game is over. If anyone could give me a hand as to how to do this it would be appreciated.

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;
        answer = fnum + snum;
 
 
        //Output of math problem
        System.out.print(fnum);
        System.out.print("+");
        System.out.println(snum);
 
        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!");
        }
 
    }
}

How do you want your little game to run?
I mean, you want to ask ten random math questions before the game is over. Do you want to keep track of how many the user gets correct and then report that score to the user after the ten questions?

You could put everything in a for/while loop and make it run 10 times (10 questions). And inside this loop keep track of how many times the user gets the math question correct with a variable, and then print out that score to the user outside your main game loop.


Also, if you want to print out a random math operator along with random operands (numbers), you can put your operators into an array of Strings and then print out a random index of that array.

Example:

 
//Declare and construct variables 
        Random randomnum = new Random();
        int fnum, snum, answer;
        int mathnumber = randomnum.nextInt(20);
        int newnumber = randomnum.nextInt(20);
 
//Declare the operator
        String[] operators = {"+", "-" , "/" , "*" };
        int randomIndex = randomnum.nextInt(3);
        String selectedOperator = operators.substring(i, i+1);
 
        //Declare and construct variables of math problem
        fnum = mathnumber;
        snum = newnumber;
 
        if(selectedOperator.equals("+")
             answer = fnum + snum;
         else if(selectedOperator.equals("-")
             answer = fnum - snum;
          else if(selectedOperator.equals("/")
             answer = fnum / snum;
          else if(selectedOperator.equals("*")
             answer = fnum * snum;
 
 
 
        //Output of math problem
        System.out.print(fnum);
        System.out.print(selectedOperator);
        System.out.println(snum);