Menu Program

package week2;

import java.util.Scanner;

public class Question3 {

    public static void main(String[] args){

            Scanner input = new Scanner(System.in);

            char letter = '\0';

            while(letter != 'q'){

            System.out.println("Enter one of these letters: a, b, c, d, e, q. q terminates the program!");
            System.out.println("Enter here: ");

            letter = input.nextLine().trim().toLowerCase().charAt(0);

                    switch(letter){
                        case 'a':
                                optionA();
                                break;
                        case 'b':
                                optionB();
                                break;
                        case 'c':
                                optionC();
                                break;
                        case 'd':
                                optionD();
                                break;
                        case 'e':
                                optionE();
                                break;
                        case 'q':
                                optionQ();
                                break;
                        default:
                            System.out.println("Invalid letter entered. Try again!");
            }
        }
    }


        static void optionA(){

            System.out.println("Name: Sher Stark.");
            System.out.println("Tutor: Mark Abernethy.");
            System.out.println("Tutorial: Wednesday, 10:30 - 12:30.");
        }

        static void optionB(){

            Scanner input = new Scanner(System.in);

            float x;
            float y;
            float z;

            System.out.println("Enter the first number: ");
            x = input.nextFloat();

            System.out.println("Enter the second number: ");
            y = input.nextFloat();

            System.out.println("Enter the third number: ");
            z = input.nextFloat();

            if((x > y)&&(x > z))
            System.out.println("The first number is the largest. Its value is: " + x);
            else
            if((y > x)&&(y > z))
                        System.out.println("The second number is the largest. Its value is: " + y);
                    else
                                System.out.println("The third number is the largest. Its value is: " + z);

            float average = (x + y + z)/3;

            System.out.println("The average of the three numbers is: " + average);
    }

    static void optionC(){

            Scanner input = new Scanner(System.in);

            int m;
            int n;
            int count = 0;
            int sum = 0;

            System.out.println("Enter the first number: ");
            m = input.nextInt();

            System.out.println("Enter the second number: ");
            n = input.nextInt();

            if(m > n){

                int temp = m;
                m = n;
                n = temp;

            }

            for(int i = m; i<= n; i++){
                System.out.print(i + " ");

                count++;
                if(count == 5){
                    count = 0;
                    System.out.println();
                }

                if(i % 2 != 0)
                    sum = sum + i;
            }
            if(count > 0)
                System.out.println();

            System.out.println("The sum of all the odd numbers is: " + sum);

    }

    static void optionD(){

            Scanner input = new Scanner(System.in);

            int s1;
            int s2;
            int s3;

            System.out.println("Enter the first number: ");
            s1 = input.nextInt();

            System.out.println("Enter the second number: ");
            s2 = input.nextInt();

            System.out.println("Enter the third number: ");
            s3 = input.nextInt();

            System.out.println("The numbers you have entered are: " + s1 + " " + s2 + " " + s3);

            if((s1 + s2 > s3)&&(s1 + s3 > s2)&&(s2 + s3 > s1))
                System.out.println("This is a valid triangle.");
            else
                System.out.println("This is not a valid triangle.");
    }

    static void optionE(){

            Scanner input = new Scanner(System.in);

            int num;

            System.out.println("Please enter a positive integer: ");
            num = input.nextInt();

            while(num > 0){

                boolean prime = true;

            for(int i = 2; i <= num/2; i++){

                        if(num % i == 0){
                        prime = false;
                            break;
                }
                    }

            if(prime == true){
                        System.out.println("It is a prime number.");
                        break;
                    }
                    else{
                        System.out.println("It is not a prime number.");
                        break;
            }
                }
    }

    static void optionQ(){

            System.out.println("Quitting program. See you next time!");
        }
}