Methods Need help

[kennith stomps]

Anyone know what my problem in this code is? I am inputting it as all the guidelines say but can't get it rite.

import java.util.Scanner;

public class aCalculateP {

	public static void main(String[] args) {
		int input=0;

		int menuSelection = getMenuOption();
	}

	private static int getMenuOption(int i) {
		
		return 0;
	}
}
	public static void getMenuOption(i) {
		System.out.println("\tArray Calculations calculator \n");
		System.out.println("1. Add\n");
		System.out.println("2. Subtract\n");
		System.out.println("3. Multiple\n");
		System.out.println("4. Divide\n");
		System.out.println("5. Dot Product\n");
		System.out.println("6. Generate Random Number\n");
		System.out.println("7. Quit\n");
		System.out.println("Make your selection\n");
		//activate scanner
		Scanner input = new Scanner(System.in);
		int i=0;
		int number = input.nextInt();
	}
		

[Knute Snortum]

You are calling the menu method like this

int menuSelection = getMenuOption();

which means the method should return an int and have no parameters.  But your two method declarations look like this:

private static int getMenuOption(int i) {

This declares a method that returns an int (good) and takes one parameter (huh?).  This declaration

public static void getMenuOption(i) 

is a syntax error, since method parameters need to be typed.  It also returns void, which is not what you need.

So, how would you declare a method that returns an int and has no parameters?

[kennith stomps]

I still have no idea how it is supposed to be done. This appears to be the exact way all the textbooks say to do it. How do you input qt1

[kennith stomps]

**how do you input ints then**

[kennith stomps]

when I delete the variable n1, all it does is give me an error that I need a value of n1.

[Knute Snortum]

Based on how you are calling it, the getMenuOption() method signature should look like this:

private static int getMenuOption() {

Because you're declaring that the method returns an int, you need a return statement at the end of your method:

return number;

You don't need the two declarations, just one.  But there is another problem with your code.  On line 15 you close the class, then you try to write a method outside of the class.  Bring your method inside the brace or just move the brace to the bottom of the code.

[Knute Snortum]

I merged your stuff with the following thread. I hope that is okay by you.

[kennith stomps]

Hello, I posted this question already, but do not think I asked it properly. I do not know why this code is failing, it says it is a double declared variable but that is not the case.
\

import java.util.Scanner;

public  class aCalculateP {

	public static void main(String[] args) {
		//menu choice variable
	int i = 0;

		int menuSelection = getMenuOption(i);
	
	}


//getmenu input method
	public static int getMenuOption(int n1) {
		System.out.println("\tArray Calculations calculator \n");
		System.out.println("1. Add\n");
		System.out.println("2. Subtract\n");
		System.out.println("3. Multiple\n");
		System.out.println("4. Divide\n");
		System.out.println("5. Dot Product\n");
		System.out.println("6. Generate Random Number\n");
		System.out.println("7. Quit\n");
		System.out.println("Make your selection\n");
		//activate scanner
		Scanner input = new Scanner(System.in);
		
	
	}
		
}
		
		

[Knute Snortum]

This is the error I get:
This method must return a result of type int aCalculateP.java /Play/src line 15 Java Problem It's important to copy the exact error message and the line number and program name.

This is telling you what I told you above, that you are declaring a method that returns an int, but you have no return statement.

[kennith stomps]

Here is the updated code, now receiving the error that int1 cannot be resolved to a variable.

import java.util.Scanner;

public  class aCalculateP {

	public static void main(String[] args) {
		//menu choice variable
	int i = 0;

		int menuSelection = getMenuOption(i);
	
	}


//getmenu input method
	private static int getMenuOption() {
		System.out.println("\tArray Calculations calculator \n");
		System.out.println("1. Add\n");
		System.out.println("2. Subtract\n");
		System.out.println("3. Multiple\n");
		System.out.println("4. Divide\n");
		System.out.println("5. Dot Product\n");
		System.out.println("6. Generate Random Number\n");
		System.out.println("7. Quit\n");
		System.out.println("Make your selection\n");
		//activate scanner
		Scanner input = new Scanner(System.in);
		int int1 = input.nextInt();
		
		return intl;
	
	}
		
}

[Knute Snortum]

Remember to include the line number with the error message.

Look carefully at the variable name you declare and the variable you return.  They are not the same, although they look similar.  This is why I never use "1" in my variable names.

[kennith stomps]

line 27 i declare int1
line 29 I return int1 ... WHich is what I am wanting to do, I want to return the menu selection

[kennith stomps]

line 27 i declare int1
line 29 I return int1 ... WHich is what I am wanting to do, I want to return the menu selection

[kennith stomps]

ohhh it's intl instead of int1, that explains it

[Knute Snortum]

Look carefully at the last letter of the two variables.  One is a number one, and the other is the letter el.

[Knute Snortum]

kennith stomps wrote:ohhh it's intl instead of int1, that explains it

Ding, ding, ding!

[kennith stomps]

Now i receive the error
The method getMenuOption() in the type aCalculateP is not applicable for the arguments (int)

import java.util.Scanner;

public  class aCalculateP {

	public static void main(String[] args) {
		//menu choice variable
	int i = 0;

		int menuSelection = getMenuOption(i);
	
	}


//getmenu input method
	private static int getMenuOption() {
		System.out.println("\tArray Calculations calculator \n");
		System.out.println("1. Add\n");
		System.out.println("2. Subtract\n");
		System.out.println("3. Multiple\n");
		System.out.println("4. Divide\n");
		System.out.println("5. Dot Product\n");
		System.out.println("6. Generate Random Number\n");
		System.out.println("7. Quit\n");
		System.out.println("Make your selection\n");
		//activate scanner
		Scanner input = new Scanner(System.in);
		int int1 = input.nextInt();
		
		return int1;
	
	}
		
}
		
		

[Knute Snortum]

int menuSelection = getMenuOption(i);

Why are you calling getMenuOption() with a parameter?

[kennith stomps]

I was putting i inside the parameter so that I can define what i is(which is the menu selection) and return that to the main method where I can then go on to perform my mathematic calculation.

[kennith stomps]

I have also tried it as such

public static void main(String[] args) {
		//menu choice variable
	int i = 0;

	getMenuOption(i);
	
	}

[kennith stomps]

I was believing that having the i in the parameter, would allow me to run the method, and have the int1 value that is returned from the method stored in the value i.

[kennith stomps]

Got it, thanks, takes a while to sink in but then it suddenly clicks. I have literally been studying methods and arrays for 15 hours the past 2 days, and it just clicked. What a great feeling! I will move onto the rest of the code that I must do, which involves arrays, if I have any other questions would it be best to start a new thread or continue on with this one?
[code]

import java.util.Scanner;

public  class aCalculateP {

public static void main(String[] args) {
//menu choice variable

getMenuOption();

}


//getmenu input method
public static int getMenuOption() {
System.out.println("\tArray Calculations calculator \n");
System.out.println("1. Add\n");
System.out.println("2. Subtract\n");
System.out.println("3. Multiple\n");
System.out.println("4. Divide\n");
System.out.println("5. Dot Product\n");
System.out.println("6. Generate Random Number\n");
System.out.println("7. Quit\n");
System.out.println("Make your selection\n");
//activate scanner
Scanner input = new Scanner(System.in);
int int1 = input.nextInt();

return int1;

}

}


[code]

[Knute Snortum]

You send arguments to a method with parameters.  Think of arguments as what you input into your method and the method parameters "receive" the input.

You don't need input into your getMenuOption() method, so it has no parameters, therefore it can't have any arguments when it's called.  You don't need them.  You call it like this:

getMenuOption();

But then you're not capturing the return value.  Your method declares that it has a return value of type int.  It also has a return statement, returning an int.  Now you need to capture that return value like this:

int i = getMenuOption();

Make sense?

[Knute Snortum]

kennith stomps wrote:Got it, thanks, takes a while to sink in but then it suddenly clicks. I have literally been studying methods and arrays for 15 hours the past 2 days, and it just clicked. What a great feeling!

Isn't it though?

I will move onto the rest of the code that I must do, which involves arrays, if I have any other questions would it be best to start a new thread or continue on with this one?

Let's stay on this thread for now.

import java.util.Scanner;

public  class aCalculateP {

	public static void main(String[] args) {
		//menu choice variable

	getMenuOption();
	
	}

//getmenu input method
	public static int getMenuOption() {
		System.out.println("\tArray Calculations calculator \n");
		System.out.println("1. Add\n");
		System.out.println("2. Subtract\n");
		System.out.println("3. Multiple\n");
		System.out.println("4. Divide\n");
		System.out.println("5. Dot Product\n");
		System.out.println("6. Generate Random Number\n");
		System.out.println("7. Quit\n");
		System.out.println("Make your selection\n");
		//activate scanner
		Scanner input = new Scanner(System.in);
		int int1 = input.nextInt();
		
		return int1;
	
	}
		
}		

Unfortunately, I don't see you capturing the return value from getMenuOption().

[kennith stomps]

I have moved onto where I am trying to get 2 double values, which I will use in my calculations. I call upon my method getOperand, and run the method, however I am not sure how to go about this, here is the specific part where I am stuck.

public static double getOperand() {
		System.out.println(" select your 2 numbers \n" );
		double num[0] = input.nextDouble();
		double num[1] = input.nextDouble();
		
		return num; 

import java.util.Scanner;

public  class aCalculateP {

	public static void main(String[] args) {
		//menu choice variable

	int choice = getMenuOption();
	
	if (choice != 7){
	getOperand();
	}	
	
	}


//getmenu input method
	public static int getMenuOption() {
		System.out.println("\tArray Calculations calculator \n");
		System.out.println("1. Add\n");
		System.out.println("2. Subtract\n");
		System.out.println("3. Multiple\n");
		System.out.println("4. Divide\n");
		System.out.println("5. Dot Product\n");
		System.out.println("6. Generate Random Number\n");
		System.out.println("7. Quit\n");
		System.out.println("Make your selection\n");
		//activate scanner
		Scanner input = new Scanner(System.in);
		int int1 = input.nextInt();
		
		return int1;
	}
	
	public static double getOperand() {
		System.out.println(" select your 2 numbers \n" );
		double num[0] = input.nextDouble();
		double num[1] = input.nextDouble();
		
		return num;
	}}
	


		

[kennith stomps]

I try it like this and it also does not work

public static double getOperand(double num[], double num[]) {
		System.out.println(" select your 2 numbers \n" );
		double num[0] = input.nextDouble();
		double num[1] = input.nextDouble();
		
		return num;

[kennith stomps]

This thread still active?

[Carey Brown]

I merged your stuff with the following thread. I hope that is okay by you.

[kennith stomps]

How do you use a method to input a value into an array, and return that array to your main method? This is what I have thus far

import java.util.Scanner;

public  class aCalculateP {

	public static void main(String[] args) {
		//menu choice variable

	int choice = getMenuOption();
	
	if (choice != 7){
	
		getOperand();
	
	}	
	
	}


//getmenu input method
	public static int getMenuOption() {
		System.out.println("\tArray Calculations calculator \n");
		System.out.println("1. Add\n");
		System.out.println("2. Subtract\n");
		System.out.println("3. Multiple\n");
		System.out.println("4. Divide\n");
		System.out.println("5. Dot Product\n");
		System.out.println("6. Generate Random Number\n");
		System.out.println("7. Quit\n");
		System.out.println("Make your selection\n");
		//activate scanner
		Scanner input = new Scanner(System.in);
		int int1 = input.nextInt();
		
		return int1;
	}
	
	public static double[] getOperand(double[] value) {
		System.out.println(" select your 2 numbers \n" );
		
		Scanner input = new Scanner(System.in);
		
		for (int i=0;i<3;i++){
			double num[] = input.nextDouble();
		}
		
	
		return num[];
	}}
	

		

		
		

[kennith stomps]

Any ideas?

[Carey Brown]

Here's a tutorial on arrays.

[kennith stomps]

I've been reading tutorial after tutorial, not one mentions how you are to use a method collecting user input to return an array to another array in the main method

[Carey Brown]

   public static double[] getOperand(double[] value) {        System.out.println(" select your 2 numbers \n" );                Scanner input = new Scanner(System.in);                for (int i=0;i<3;i++){            double num[] = input.nextDouble();        }                    return num[];    }}
What is "value"? What are you doing with it?
You've declared "num" local to the for() loop. It will not be visible outside of the loop.
You are not assigning  your double to a particular slot in the array.
You are not declaring the length of the arry.
Your return syntax is wrong.
-- read some of the tutorials again, you are missing basic syntax issues.

[kennith stomps]

Does anyone know how to?

[kennith stomps]

The tutorial mentions nothing in regards to this. I do not know how to lay it out, I simply want to use a method to send 2 values back to the main method in an array, where I can then perform calculations with those 2 values

[kennith stomps]

No tutorial I have seen has mentioned anything in regards to this

[Carey Brown]

        // declares an array of integers
        int[] anArray;

        // allocates memory for 10 integers
        anArray = new int[10];
           
        // initialize first element
        anArray[0] = 100;

This is from the link I just sent you.

[kennith stomps]

Here is my updated code with my array according to that, I still don't understand how I am to output the numArray in the  getOperand method to my main method operandsArray

import java.util.Scanner;

public  class aCalculateP {

	public static void main(String[] args) {
		//menu choice variable

	int choice = getMenuOption();
	
	if (choice != 7){
	
		double[] operandsArray;
		operandsArray = new double[1];
		operands = getOperand();
	
	}	
	
	}


//getmenu input method
	public static int getMenuOption() {
		System.out.println("\tArray Calculations calculator \n");
		System.out.println("1. Add\n");
		System.out.println("2. Subtract\n");
		System.out.println("3. Multiple\n");
		System.out.println("4. Divide\n");
		System.out.println("5. Dot Product\n");
		System.out.println("6. Generate Random Number\n");
		System.out.println("7. Quit\n");
		System.out.println("Make your selection\n");
		//activate scanner
		Scanner input = new Scanner(System.in);
		int int1 = input.nextInt();
		
		return int1;
	}
	
	public static double[] getOperand(double[] value) {
		System.out.println(" select your 2 numbers \n" );
		
		Scanner input = new Scanner(System.in);
		
		double[] numArray;
		numArray = new double[1];
		double numArray[0] = input.nextDouble();
		double numArray[1] = input.nextDouble();
		}
		
	
		return numArray;
	}