Day 16 Sample

package week3training;
import java.util.Scanner;

public class Day16A {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        double num1;

        try {
            System.out.print("Enter number: ");
            num1 = sc.nextDouble();
            System.out.println("... Computing");
        } catch (Exception e) {
            System.out.println("You entered an invalid number.");
            System.out.println("Number will default to 1");
            num1 = 1;
        }

        num1 /= 2;
        System.out.println("Half of number: " + num1);
    }
}
//-------------------

public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    int arrIndex = 0;
    int[] numArray = new int[5];


    try {
        System.out.print("Enter Array Index: ");
        arrIndex = sc.nextInt();
        System.out.print("Enter value of cell: ");
        numArray[arrIndex] = sc.nextInt();
    } catch (ArrayIndexOutOfBoundsException e) {
        System.out.println("Array index more than array size");
    } catch (Exception e) {
        System.out.println("There is an error");
    }

    for (int i = 0; i < numArray.length; i++) {
        System.out.println(i + " : " + numArray[i]);
    }
}

//-----------------------------------------
package week3training;
import java.util.Scanner;

public class Day16C {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        double num1=0, num2=0;
        String op, userInput;

        System.out.print("Enter number 1: ");
        userInput = sc.nextLine();
        if (isNumeric(userInput)) {
            num1 = Double.parseDouble(userInput);
            userInput = "";
        }
        System.out.print("Enter operator(+,-,*,/): ");
        op = sc.nextLine();
        System.out.print("Enter number 2: ");
        userInput = sc.nextLine();
        if (isNumeric(userInput)) {
            num2 = Double.parseDouble(userInput);
            userInput = "";
        }

        // calling compute method to do the calculate result
        compute(num1, num2, op);
    }

    public static boolean isNumeric(String strNum) {
        if (strNum == null) {
            return false;
        }
        try {
            double d = Double.parseDouble(strNum);
        } catch (NumberFormatException nfe) {
            return false;
        }
        return true;
    }

    public static void compute(double num1, double num2, String operator) {
        double result = 0;
        boolean validOp = true;

        switch (operator) {
            case "+":
                result = num1 + num2;
                break;
            case "-":
                result = num1 - num2;
                break;
            case "*":
                result = num1 * num2;
                break;
            case "/":
                result = num1 / num2;
                break;
            default:
                validOp = false;
        }
        if (validOp)
            System.out.println(num1 + operator + num2 + "=" + result);
        else
            System.out.println("Operator not valid");
    }
}