Square Array Program

Question

Using java, I am supposed to create a program that stores the square of the numbers 0, 1, 2 & 9 in an ArrayList of 10 elements.

I have created part of the code that displays the numbers and its squares but the program goes straight down with all the numbers and does not look organized. Can someone help me write it out like like this instead:

number: 0 square: 0

number: 1 square: 1

number: 2 square: 4

Code

public static void main(String[] args) {
    int[] temp = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9};

    for (int value : temp) {
        System.out.println(value);
    }

    for (int i = 0; i < temp.length; i++) {
        temp[i] = (int) Math.pow(temp[i], 2);
    }

    for (int value : temp) {
        System.out.println(value);
    }
}

If this is supposed to use an ArrayList, where is its usage? Or did you not actually mean an ArrayList? — KevinO
– KevinO, Commented Apr 21, 2017 at 15:23

Youcef LAIDANI · Accepted Answer · 2017-04-21 15:34:25Z

1

You need just one loop like this :

public static void main(String[] args) {
    int[] temp = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9};

    for (int i = 0; i < temp.length; i++) {
        System.out.println(temp[i] + "\t" + (int)Math.pow(temp[i], 2));
    }
}

OutPut

If you want to store your results in an ArrayList you can use :

List<int[]> array = new ArrayList<>();//create a List which take an array of int

int arr[] = new int[2];//create a temporary array of 2 elements

for (int i = 0; i < temp.length; i++) {
    System.out.println("Number: " + temp[i] + " \tSquare: " + (int) Math.pow(temp[i], 2));
    arr[0] = temp[i];//add your number to your array pos 1
    arr[1] = (int) Math.pow(temp[i], 2);//add the power to the 2ed position
    array.add(arr);//add your array to your list

}

edited Apr 21, 2017 at 15:34

answered Apr 21, 2017 at 15:19

Youcef LAIDANI

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5 Comments

KevinO Over a year ago

I believe you can just do int[] temp = new int[10]; and then instead of outputting temp[i] just output i. I would also tend to use String.format("%2d\t%3f") in the output to align the numbers.

Dustin Kingen Over a year ago

@KevinO At that point the array is not needed since it can all be done with a for loop.

KevinO Over a year ago

The OP's question required placing the results in an array.

Youcef LAIDANI Over a year ago

@KevinO what about my edit? another thing, the temp array can be {5,6,9,111,4777} so it can contain any numbers, so you can't use just i

KevinO Over a year ago

@YCF_L, If the initial array could contain numbers other than 0...9, then you are correct using the loop iterator would not work. Depends upon the specification. Good addition on the use of the ArrayList, which I took as part of the OP's question, if not the original example.

Hani · Accepted Answer · 2017-04-21 15:28:35Z

public static void main(String[] args) {
   int[] temp = {0, 1,2,3,4,5,6,7,8,9};  

     // here you are printing all your numbers in the array, so the output will be: 
     // 0
     // 1
     // ...
     // 9
     for (int value : temp) {
         System.out.println(value);
     }  


     // after that, you calculate and store them in the same array; so your array now look like this:
     // [0,1,4,9,...,81]
     for (int i = 0; i < temp.length; i++) {
         temp[i] = (int) Math.pow(temp[i], 2);
     }  


     // here you are printing again your array
     // 0
     // 1
     // 4
     // ...
     // 81
     for (int value : temp) {
         System.out.println(value);
     } 
 }

to get your desired outcome, you have to calculate the number before printing everything... one option will be to create another array

int[] square = new int[9];

calculate in the first for loop and save the result in the square array and print them, something like this:

for (int i = 0; i < temp.length; i++) {
    square[i] = (int) Math.pow(temp[i],2);
    System.out.println("number " + temp[i] + " square: " + square[i]);
}

KevinO · Accepted Answer · 2017-04-21 15:34:11Z

0

Assuming the original question which referred to an ArrayList was correct (the OP's example only had an array), and assuming the results are supposed to be stored in the array (per the question), then the following will work:

public static void main(String[] args)
{
  // instantiate ArrayList
  List<Double> array = new ArrayList<>();

  // load the values
  for (int i = 0; i < 10; ++i) {
    array.add(i, Math.pow(i, 2));
  }

  // output
  for (int i = 0; i < array.size(); ++i) {
    System.out.println(String.format("%2d\t%3.0f", i, array.get(i)));
  }
}

Output:

answered Apr 21, 2017 at 15:34

KevinO

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Comments

pringi · Accepted Answer · 2017-04-27 09:56:49Z

0

Try this :

public static void main(String[] args) {
  int[] temp = {0, 1,2,3,4,5,6,7,8,9};  

  for (int value : temp) {  
         System.out.println("number : "value);  
  }  

  for (int i = 0; i < temp.length; i++) {  
    temp[i] = (int) Math.pow(temp[i], 2);  
  }  

  for (int value : temp) {  
    System.out.println(" square : " + value + "\n");
  }
}

edited Apr 27, 2017 at 9:56

pringi

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answered Apr 21, 2017 at 15:24

TheTinyCat

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