java Array Calculator

I keep getting an error for line 84 " if (operand2 != 0) { "

and line 91 " return (double.null); "

import java.util.Arrays; import java.util.Scanner;

public class ArrayCalc {

private static final double[] NaN = null;

private static Scanner input;

private static Scanner input2;

private static Scanner input3;

public static int getMenuOption() {

input = new Scanner(System. in );

int invalid = 0;

while (invalid < 10) {

// Menu list

System.out.println(" Menu ");

System.out.println("1. Add");

System.out.println("2. Subtract");

System.out.println("3. Multiply");

System.out.println("4. Divide");

System.out.println("5. Dot product");

System.out.println("6. Generate Random Number");

System.out.println("7. Quit");

System.out.println("");

System.out.println("What would you like to do?");

int menuOption = input.nextInt();

if ((menuOption <= 7) && (menuOption > 0)) {

return (menuOption);

} else {

System.out.println("Sorry, " + menuOption + " is not an option.");

invalid++;

}

}

System.out.println("Too many invalid inputs. Try again later");

System.exit(0);

return (0);

}

public static double[] getOperand(String prompt, int size) {

return null;

}

public static double getOperand(String prompt) {

System.out.println(prompt);

input = new Scanner(System. in );

return (input.nextDouble());

}

//Addition

public static double[] addition(double[] operand1, double[] operand2) {

double[] resultset = new double[operand1.length];

for (int i = 0; i < operand1.length; i++)

resultset[i] = operand1[i] + operand2[i];

return resultset;

}

//Subtraction

public static double[] subtraction(double[] operand1, double[] operand2) {

double[] resultset = new double[operand1.length];

for (int i = 0; i < operand1.length; i++)

resultset[i] = operand1[i] - operand2[i];

return resultset;

}

//Multiplication

public static double[] multiplication(double[] operand1, double[] operand2) {

double[] resultset = new double[operand1.length];

for (int i = 0; i < operand1.length; i++)

resultset[i] = operand1[i] * operand2[i];

return resultset;

}

//Division

public static double[] division(double[] operand1, double[] operand2) {

if (operand2 != 0) {

double[] resultset = new double[operand1.length];

for (int i = 0; i < operand1.length; i++)

resultset[i] = operand1[i] / operand2[i];

return resultset;

} else {

System.out.println("Divisor cannot be zero");

return (double.NaN);

}

//Dot Product

public static double[] dotProduct(double[] operand1, double[] operand2) {

double[] resultset = new double[operand1.length];

for (int i = 0; i < operand1.length; i++)

resultset[i] = operand1[i] + operand2[i] + operand1[i] * operand2[i];

return resultset;

}

//Random

public static double random(double lowerLimit, double upperLimit, int size) {

double lower = getOperand("What is the lower limit?");

double upper = getOperand("What is the upper limit?");

double randomVal = ((double)(Math.random() * (upper - lower)) + lower);

return (randomVal);

}

public static void main(String[] args) {

input2 = new Scanner(System. in );

double[] array1 = null;

double[] array2 = null;

int arraysize = 0;

int menuOption = getMenuOption();

while ((menuOption <= 7) && (menuOption > 0)) {

if (menuOption <= 5) {

System.out.println("How many values are in the arrays?");

arraysize = input2.nextInt();

//1st array

array1 = new double[arraysize];

System.out.println("Enter the values in the first array, separated by spaces: ");

input2.nextLine();

String number = input2.nextLine();

for (int i = 0; i < arraysize; i++)

array1[i] = Integer.parseInt(number.split(" ")[i]);

//2nd array

array2 = new double[arraysize];

System.out.println("Enter the values in the secound array, separated by spaces: ");

number = input2.nextLine();

for (int i = 0; i < arraysize; i++)

array2[i] = Integer.parseInt(number.split(" ")[i]);

}

}

if (menuOption == 1) {

double[] results = addition(array1, array2);

for (int i = 0; i < arraysize; i++)

System.out.print(results[i] + " ");

menuOption = getMenuOption();

} else if (menuOption == 2) {

double[] difference = subtraction(array1, array2);

for (int i = 0; i < arraysize; i++)

System.out.println(difference[i] + " ");

//Subtraction

menuOption = getMenuOption();

} else if (menuOption == 3) {

double[] product = multiplication(array1, array2);

for (int i = 0; i < arraysize; i++)

System.out.println(product[i] + " ");

//Multiplication

menuOption = getMenuOption();

} else if (menuOption == 4) {

double[] quotient = division(array1, array2);

for (int i = 0; i < arraysize; i++)

System.out.println(quotient[i] + " ");

//Division

menuOption = getMenuOption();

} else if (menuOption == 5) {

} else if (menuOption == 6) {

double randomVal = random(array1, array2);

System.out.println(randomVal);

//Displays a random integer between an upper and a lower limit

menuOption = getMenuOption();

} else if (menuOption == 7) {

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

System.exit(0);

}

}

private static double random(double[] array1, double[] array2) {

// TODO Auto-generated method stub

return 0;

}

}