Thread: Need help displaying the location of array index

Hi all, just joined this forum and looking for a little advice with my code. My project was to create an array holding 10 integers and populate the array with 10 random numbers. Then ask the user to guess the number. Prompt the user with a while loop if their input is out of range. Determine if the users number is in the array, and display which index location the number is in. I got most of the code done but am having trouble displaying the index location. Any help is appreciated.

import javax.swing.*;
 
public class Homework4 {
 
	public static void main(String[] args) {
 
		int[] numarray = new int [10];		
		char repeatcode = 'y';
 
		for ( int i = 0 ; i < numarray.length ; i++ ) {
 
			while ( repeatcode == 'y' ) {
 
				numarray[i] = (int) (Math.random() * 100);
				int userinput = Integer.parseInt(JOptionPane.showInputDialog ( "Guess a number between 1 and 100" ));
 
				if ( userinput < 1 || userinput > 100 ) {
 
					JOptionPane.showMessageDialog(null, "Your number wasn't in the parameters" );
				}
				else {
					if ( userinput != numarray[i] ) {
 
						JOptionPane.showMessageDialog(null, "THE NUMBER IS WRONG! Thanks for playing" );
 
					} // ends if
					else  {
 
						JOptionPane.showMessageDialog(null, "WINNER!!!!\n\nYou guessed the number! Thanks for playing " + "\nThe number is stored at position " + numarray.length[i] );
 
					} // ends else
 
				}
				repeatcode = JOptionPane.showInputDialog ( "Do you want to play again? (y/n)" ).charAt(0);
 
			} // ends while loop
		} // ends for loop
	} // ends public static void main
} // ends public class Homework4

I have to create a variable that holds the index location? I didn't know that, how can i go about doing that? and where would i declare that variable?? I appreciate your help. Just keep in mind this is an intro class to java

"i" would be the random number that gets inserted into the 10 index locations

isnt the for loop and math.random assigning random numbers to those locations? or should i just have the math.random only in the for loop?

yea it should populate the 10 random numbers. and keep on asking the user to guess the number, the numbers shouldn't change

the code compiles and runs, but im not sure if its populating all 10 allocated spots.

how can i test it to see if it does completely fill the array?

If the number is negative or over 100 it prompts the user that their number was invalid. If gives me the wring number prompt and after a while if i guess that correct number it works. but im not sure if it completely fills all 10 or its just checking the first index position

Originally Posted by PCn3rd51

the code compiles and runs, but im not sure if its populating all 10 allocated spots.

I guess all the 10 locations are not getting populated. First location gets populated and then it asks the player to enter the number, then in next iteration the second location gets populated and it again asks the user for the input.

Originally Posted by PCn3rd51

how can i test it to see if it does completely fill the array?

To debug, you can print the values of the array in each iteration.

You've got some logic errors I saw pretty early on. I do believe your assignment wants you to populate an array with 10 random numbers THEN start asking the user for their answers.
The way you have yours setup, it will only ever have 1 number in the array on most occasions. You should have your while loop outside of your for loop.

All of you have been a big help. I fixed it so that it is now generating 10 random numbers every time the while loop starts. My only problem now is that its saying that int i needs to be initialized. Its on the second if statment **** if ( userinput != numarray[i] ) ****

You all have been a huge help and cant thank you enough

import javax.swing.*;
 
public class Homework4 {
 
	public static void main(String[] args) {
 
		int[] numarray = new int [10];
		char repeatcode = 'y';
 
			while ( repeatcode == 'y' ) {
 
				for ( int i = 0 ; i < numarray.length ; i++ ) {
 
					numarray[i] = (int) (Math.random() * 100);
				}
 
				System.out.println("The random numbers are: "+ java.util.Arrays.toString(numarray));
 
				int userinput = Integer.parseInt(JOptionPane.showInputDialog ( "Guess a number between 1 and 100" ));
 
				if ( userinput < 1 || userinput > 100 ) {
 
					JOptionPane.showMessageDialog(null, "Your number wasn't in the parameters" );
				}
				else {
					if ( userinput != numarray[i] ) {
 
						JOptionPane.showMessageDialog(null, "THE NUMBER IS WRONG! Thanks for playing" );
 
					}
					else  {
 
						JOptionPane.showMessageDialog(null, "WINNER!!!!\n\nYou guessed the number! Thanks for playing " + "\nThe number is stored at position "  );
 
					}
 
				}
				repeatcode = JOptionPane.showInputDialog ( "Do you want to play again? (y/n)" ).charAt(0);
 
			}
	} //
} //

well i would be one of the 10 random numbers. so how would i phrase my if statement if i want the userinput to not equal one of those 10 numbers?

Originally Posted by Norm

One place I see i being used is in the for loop to index into the array where the random numbers are being stored. i does not contain a random number.


There needs to be a loop that iterates through all the elements in the array and compares the user input against each element in the array.

It seems a little redundant to nest 10 if statements to test that, is there an easier way of doing that?

if ( userinput != numarray[1] ) {
 
	if userinput != numarray[2] ) {
 
		if userinput != numarray[3] ) {
 
			if userinput != numarray[4] ) {
 
				if userinput != numarray[5] ) {
 
					if userinput != numarray[6] ) {
 
					}
				}
			}
		}
	}
}

Disregard my last post, wasn't thinking straight lol....

for ( int arrayindex = 0 ; arrayindex < numarray.length ; arrayindex++ ) {
 
					numarray[arrayindex] != userinput;
 
				}

and that would go in the else?

SOLVED! Figured it out last night but it works perfectly. I want to thank all who helped me. Feel free to test it out for yourselves

import javax.swing.*;
 
public class Homework4a {
 
	public static void main(String[] args) {
 
		int[] numarray = new int [10];
 
		for ( int i = 0 ; i < numarray.length ; i++ ) {
 
			numarray[i] = (int) (Math.random() * 100 + 1);
		}
 
		System.out.println("The random numbers are: "+ java.util.Arrays.toString(numarray));
 
		int userinput = Integer.parseInt(JOptionPane.showInputDialog ( "Guess a number between 1 and 100" ));
 
		while ( userinput > 100 || userinput < 1 ) {
 
			JOptionPane.showMessageDialog(null, "Your number wasn't in the parameters" );
			userinput = Integer.parseInt(JOptionPane.showInputDialog ( "Guess a number between 1 and 100" ));
 
		}
 
		for ( int j = 0 ; j < numarray.length ; j++ ) {
 
			if ( numarray[j] != userinput ) {
 
 
			}
			else {
 
				JOptionPane.showMessageDialog(null, "WINNER!!!!\n\nYou guessed the number! Thanks for playing " + "\nThe number is stored at position " + j  );
				return;
 
			}
 
		}
 
		JOptionPane.showMessageDialog(null, "The answer is not in correct" );
 
	}
 
}