import java.util.Scanner; import java.util.Random; class MathTutor { public stat

ID: 3908404 • Letter: I

Question

import java.util.Scanner;
import java.util.Random;

class MathTutor
{
public static void main(String[] args)
{
int number1;
int number2;
int sum;
int userAnswer;

Scanner keyboard = new Scanner(System.in);

Random randomNumbers = new Random();

number1 = randomNumbers.nextInt(100);
number2 = randomNumbers.nextInt(100);

// Display an addition problem.
System.out.println("What is the answer to the " +
"following problem?");
System.out.print(number1 + " + " +
number2 + " = ? ");

sum = number1 + number2;

userAnswer = keyboard.nextInt();

if (userAnswer == sum)
System.out.println("Correct!");
else
{
System.out.println("Sorry, wrong answer. " +
"The correct answer is " +
sum);
}
}
}

2. Using MathTutor.java on page 250 make the following changes a. Do a random selection on the operation to perform. You can do this by running a generator with only 4 numbers and using a switch to pick your operator. b. Keep count of right and wrong answers and display the running totals C. "Emcompass" program in a loop to continue the game.

Explanation / Answer

MathTutor.java (Changes made are in bold)

import java.util.Scanner;

import java.util.Random;

//MathTutor class begins

class MathTutor

{

//main() begins

public static void main(String[] args)

{

//Variable declarations

int number1;

int number2;

int result = 0;

int userAnswer;

int correctCount = 0;

int incorrectCount = 0;

char operator = ' ';

char playAgain;

//Objects of Scanner and Random class

Scanner keyboard = new Scanner(System.in);

Random randomNumbers = new Random();

//Loop runs until user does not want to play anymore

{

//Generate 2 random numbers (operands) from 0 to 99

number1 = randomNumbers.nextInt(100);

number2 = randomNumbers.nextInt(100);

//Generates a random number and it sets the operator

switch(randomNumbers.nextInt(4))

{

//Addition

case 0:

operator = '+';

result = number1 + number2;

break;

//Subtraction

case 1:

operator = '-';

result = number1 - number2;

break;

//Multiplication

case 2:

operator = '*';

result = number1 * number2;

break;

//Division

case 3:

operator = '/';

result = number1 / number2;

break;

}

//Print the problem

System.out.println("What is the answer to the following problem?");

System.out.print(number1 + " " + operator + " " + number2 + " = ? ");

//Also tell the user to enter only the integer for division problems

if(operator == '/')

System.out.print("(Enter integer part only) ");

//Input answer

userAnswer = keyboard.nextInt();

//If answer entered by user is correct, then print "Correct!" and increase count for correct answers by 1

if (userAnswer == result)

{

System.out.println("Correct!");

correctCount++;

}

//Otherwise print message and increase count for incorrect answers by 1

else

{

System.out.println("Sorry, wrong answer. The correct answer is " + result);

incorrectCount++;

}

//Output the count for correct and incorrect answers

System.out.println("Correct answer: " + correctCount);

System.out.println("Incorrect answer: " + incorrectCount);

//Ask user if want to play again

System.out.print("Do you want to play again? (Y/N) ");

//Input user choice

//The following statement is used to input a single character and ignores the characters except 1st character

playAgain = keyboard.next().charAt(0);

System.out.println();

//Run the loop again if user entered 'Y' or 'y'

}while(playAgain == 'Y' || playAgain == 'y');

//Always remember to close Scanner class object

keyboard.close();

}

//main() ends

}

//MathTutor class ends

Output for a test run is also provided. User input is in bold.