Try the following:
int[][] multi = new int[5][10];
... which is a short hand for something like this:
int[][] multi = new int[5][];
multi[0] = new int[10];
multi[1] = new int[10];
multi[2] = new int[10];
multi[3] = new int[10];
multi[4] = new int[10];
Note that every element will be initialized to the default value for int, 0, so the above are also equivalent to:
int[][] multi = new int[][] {
{ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
{ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
{ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
{ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
{ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 }
};
... or, more succinctly,
int[][] multi = {
{ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
{ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
{ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
{ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
{ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 }
};
Syntax for creating a two-dimensional array in Java - Stack Overflow
Need help in Java specifically 2D Array
I am not understanding two dimensional arrays.
java - Two-dimensional array of different types - Stack Overflow
Try the following:
int[][] multi = new int[5][10];
... which is a short hand for something like this:
int[][] multi = new int[5][];
multi[0] = new int[10];
multi[1] = new int[10];
multi[2] = new int[10];
multi[3] = new int[10];
multi[4] = new int[10];
Note that every element will be initialized to the default value for int, 0, so the above are also equivalent to:
int[][] multi = new int[][] {
{ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
{ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
{ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
{ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
{ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 }
};
... or, more succinctly,
int[][] multi = {
{ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
{ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
{ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
{ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
{ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 }
};
We can declare a two dimensional array and directly store elements at the time of its declaration as:
int marks[][]={{50,60,55,67,70},{62,65,70,70,81},{72,66,77,80,69}};
Here int represents integer type elements stored into the array and the array name is 'marks'. int is the datatype for all the elements represented inside the "{" and "}" braces because an array is a collection of elements having the same data type.
Coming back to our statement written above: each row of elements should be written inside the curly braces. The rows and the elements in each row should be separated by a commas.
Now observe the statement: you can get there are 3 rows and 5 columns, so the JVM creates 3 * 5 = 15 blocks of memory. These blocks can be individually referred ta as:
marks[0][0] marks[0][1] marks[0][2] marks[0][3] marks[0][4]
marks[1][0] marks[1][1] marks[1][2] marks[1][3] marks[1][4]
marks[2][0] marks[2][1] marks[2][2] marks[2][3] marks[2][4]
NOTE:
If you want to store n elements then the array index starts from zero and ends at n-1.
Another way of creating a two dimensional array is by declaring the array first and then allotting memory for it by using new operator.
int marks[][]; // declare marks array
marks = new int[3][5]; // allocate memory for storing 15 elements
By combining the above two we can write:
int marks[][] = new int[3][5];
I'm creating a program that will sum up the outer squares(1) as well as the inner ones(2)(3).
I've already figured out how to sum up the outer boundaries. But, I can't sum up the inner boundaries.
The current dimension is 6x6 but it also needs to be flexible depending on user preference.
Can anyone help? T.T
| 1 | 1 | 1 | 1 | 1 | 1 |
|---|---|---|---|---|---|
| 1 | 2 | 2 | 2 | 2 | 1 |
| 1 | 2 | 3 | 3 | 2 | 1 |
| 1 | 2 | 3 | 3 | 2 | 1 |
| 1 | 2 | 2 | 2 | 2 | 1 |
| 1 | 1 | 1 | 1 | 1 | 1 |
Hey guys! I made a project last week using one dimensional arrays, and it went easy and I felt proud. Now, I got to two dimensional arrays and it all went south, fast. I will post last weeks code to help anyone understand this ones purpose.
Purpose of this weeks project is to make a lottery of three numbers, if a players numbers match the three drawn numbers, they win. Simple as that. My outputs are horrific looking though, and I am sure I can do this more simply than I am. My outputs look like "Player Number [I@3b6eb2ec:[I@3b6eb2ecPlayer Number [I@3b6eb2ec:[I@1e643fafPlayer Number [I@3b6eb2ec:[I@6e8dacdfPlayer Number [I@3b6eb2ec:[I@7a79be86". I haven't made the if statement to match the drawn numbers to the players numbers yet.
Powerball (Old Good Code): https://pastebin.com/xeGR5pQM
Lottery (Unfinished): https://pastebin.com/hQUhvTRk
I am not sure I am following, but you might be looking for a Map<Integer,String>. or Map<Integer,List<String>>. [have a look on List, and HashMap]
Map allows association of the key [Integer] to the value [String or List].
Map also allows fast lookup of key, and its attached value.
(*) You should use Map<Integer,List<String>> if you want to attach more then one String per Integer, or alternatively you can use apache commons MultiMap
Arrays can only contain one type. If that type happens to be Object then it can store Object and any of its sub-types, but that doesn't really sound like what you're trying to accomplish here.
It sounds like what you're describing is a 2D array to store database information, with each element in the array being a column in one of the rows. This isn't an array of records, it's an array of column data.
Instead, just store a one-dimensional array of records, where each element of the array is a reference to the entire DB row.