This is array initializer syntax, and it can only be used on the right-hand-side when declaring a variable of array type. Example:
int[] x = {1,2,3,4};
String[] y = {"a","b","c"};
If you're not on the RHS of a variable declaration, use an array constructor instead:
int[] x;
x = new int[]{1,2,3,4};
String[] y;
y = new String[]{"a","b","c"};
These declarations have the exact same effect: a new array is allocated and constructed with the specified contents.
In your case, it might actually be clearer (less repetitive, but a bit less concise) to specify the table programmatically:
double[][] m = new double[4][4];
for(int i=0; i<4; i++) {
for(int j=0; j<4; j++) {
m[i][j] = i*j;
}
}
This is array initializer syntax, and it can only be used on the right-hand-side when declaring a variable of array type. Example:
int[] x = {1,2,3,4};
String[] y = {"a","b","c"};
If you're not on the RHS of a variable declaration, use an array constructor instead:
int[] x;
x = new int[]{1,2,3,4};
String[] y;
y = new String[]{"a","b","c"};
These declarations have the exact same effect: a new array is allocated and constructed with the specified contents.
In your case, it might actually be clearer (less repetitive, but a bit less concise) to specify the table programmatically:
double[][] m = new double[4][4];
for(int i=0; i<4; i++) {
for(int j=0; j<4; j++) {
m[i][j] = i*j;
}
}
You can initialize an array by writing actual values it holds in curly braces on the right hand side like:
String[] strArr = { "one", "two", "three"};
int[] numArr = { 1, 2, 3};
In the same manner two-dimensional array or array-of-arrays holds an array as a value, so:
String strArrayOfArrays = { {"a", "b", "c"}, {"one", "two", "three"} };
Your example shows exactly that
double m[][] = {
{0*0,1*0,2*0,3*0},
{0*1,1*1,2*1,3*1},
{0*2,1*2,2*2,3*2},
{0*3,1*3,2*3,3*3}
};
But also the multiplication of number will also be performed and its the same as:
double m[][] = { {0, 0, 0, 0}, {0, 1, 2, 3}, {0, 2, 4, 6}, {0, 3, 6, 9} };
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I strongly suspect it is throwing an ArrayIndexOutOfBoundsException which is getting swallowed outside this method.
You are creating an array of size n, in this case 10, but your counter goes from zero to f (also 10) which is a total of 11 elements. So there's an off-by-one in at least one of those.
Look through your code and find the bit that says
catch (Exception e) {
}
and change it to
catch (Exception e) {
e.printStackTrace();
}
to help catch this kind of error more easily.
Unfortunately I can't post comments yet as this isn't a concrete answer but I have checked and run your code and it runs fine for me. Substituting in a fixed coefficient and degree show that the bracketing is all fine and that you aren't (as I suspected) reinitialising the resultArray variable in an inner scope.
Is this a direct copy/paste of the problematic code that you have?
Typically when I have an issue like this it is nothing to do with the assignment but instead it is because 'resultsArray' is actually 2 different variables that I have erroneously allocated but which I am receiving no errors for because of polymorphism.
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];