Java Help

[Ryano]

I am not sure if I am in the right forum but I am writing a code in Java to produce random multiplication. I wrote it in C++ but I am kinda new to Java. Can anyone help me translate this program that I wrote in c++ to Java.

using std::cin;
using std::endl;

void multiplication();

int main()
{
multiplication();

return 0;
}
void multiplication()
{
int x;
int y;
int response = 0;

while ( response != -1 ) {
x = rand() % 10;
y = rand() % 10;

cout << " How much is " << x << " times " << y
<< " ( -1 to End ) ? : ";
cin >> response;

while ( response != -1 && response != x * y ) {
cout << " No. Please try again: " ;

cin >> response;

} //End While

if ( response != -1)
cout << "Very Good!\n\n";

} //End while

} // End function multiplication

[Bluefox815]

First off, a few pointers (see comments)

Code:

using std::cin;
using std::endl; // #include changes to import, there are no namespaces

void multiplication();  // this isn't needed no matter where your functions (or methods, as they're called in Java) are placed

/* main changes to
public static void main(String[] args) {} // notice that return type is void
*/
int main()
{
multiplication();

return 0;
}
void multiplication()
{
int x;
int y;
int response = 0;

while ( response != -1 ) {
x = rand() % 10; // I'm not sure what you tried to do here
y = rand() % 10; // but these two would change

cout << " How much is " << x << " times " << y << " ( -1 to End ) ? : ";  // cout changes to System.out.print(stuffToWrite) and << changes to a plus sign (+)
cin >> response; // cin is trickier, too much to explain

while ( response != -1 && response != x * y ) {
cout << " No. Please try again: " ;

cin >> response;

} //End While

if ( response != -1)
cout << "Very Good!\n\n";

} //End while

} // End function multiplication

I didn't know how new you were, so I just converted everything I know.

I would convert the whole program to Java but I can't see what you are doing with "rand() % 10", if you tell me what rand() does then I should be able to convert it for you, unless you think you have it down.

[hardwired]

Code:

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

public class MultiplyTest {
    static Random seed = new Random();
    static Scanner scanner;

    public static void main(String[] args) {
        scanner = new Scanner(System.in);
        multiply();
        scanner.close();
    }

    private static void multiply() {
        int response = 0;

        while(response != -1) {
            int x = 1 + seed.nextInt(10);  // [ 1 <= x <= 10]
            int y = 1 + seed.nextInt(10);
            System.out.print("How much is " + x +
                               " times " + y + " ? : ");
            try {
                response = Integer.parseInt(scanner.nextLine());
            } catch(NumberFormatException e) {
                System.out.println("number format: " + e.getMessage());
            }
            
            while(response != -1 && response != x*y) {
                System.out.print("No. Please try again: ");
                try {
                    response = Integer.parseInt(scanner.nextLine());
                } catch(NumberFormatException e) {
                    System.out.println("number format: " + e.getMessage());
                }
            }

            if(response != -1)
                System.out.println("Very Good");

        }
    }
}