使用for循环创建多个数组

Question

I would like to make a program where the user can input the number of variables and fill every variable with certain values. For example, the User inputs that he/she wants to make 10 arrays, then the User inputs that the first array should have 5 elements and the User fills that array with values, then the User wants the second array to have 4 elements and does the same and so on.

This is the code I was using, but it doesn't work:

public static void main(String[] args){
    Scanner s = new Scanner(System.in);
    System.out.println("Enter the numbers of variables: ");
    int i = s.nextInt();

    for(int j = 0;j < i;j++){
        int[] var = new int[j];
        System.out.println("Enter the number of values: ");
        int p = s.nextInt();
        for(int q = 0;q < p;p++){
            int n = s.nextInt();
            var[q] = n;
        }
    }
}

And how could I compare these arrays that the user inputs?

Answer 1

The problem is that each time you are creating the array. try this:

Scanner s = new Scanner(System.in);
System.out.println("Enter the numbers of variables: ");
int i = s.nextInt();
int[][] var = new int[i][];
for(int j = 0;j < i;j++){

    System.out.println("Enter the number of values: ");
    int p = s.nextInt();
    var[j] = new int[p];
    for(int q = 0;q < p;p++){
        int n = s.nextInt();
        var[j][q] = n;
    }
}

Instead of creating a one dimensional array, you create a jagged array. Essentially, a 2d array is an array of arrays. that way the user inputs the number of arrays ( i ) and then continues to fill the arrays.

To check whether two collections have no commons values, you can use

Collections.disjoint();

For other operations, you can look here

Answer 2

This should work (with bidimensionnal array)

    public static void main(String[] args){
        Scanner s = new Scanner(System.in);
        System.out.println("Enter the numbers of variables: ");
        int i = s.nextInt();
        int[][] var = new int[i][];
        for(int j = 0;j < i;j++){
            System.out.println("Enter the number of values: ");
            int p = s.nextInt();
            var[j] = new int[p];
            for(int q = 0;q < p;q++){
                int n = s.nextInt();
                var[j][q] = n;
            }
        }
    }

You have to replace the incrementation in the second loop too ("q++" instead of "p++")

Answer 3

This should work and solve their first point

    Scanner s = new Scanner(System.in);
    System.out.println("Enter the numbers of variables: ");
    int i = s.nextInt();

    int[][] var = new int[i][];

    for(int j = 0;j < i;j++){
         System.out.println("Enter the number of values: ");
         int p = s.nextInt();
         while (p>0)
         {
            var[j] = new int[p];
            for(int q=0;q < p;q++){
               System.out.println("Value number : " +(q+1) + " For Array Number "+  (j+1));
               int n = s.nextInt();
               var[j][q] = n;
            }
             p-=1;
         }
    }