Operator[][] overload
Is it possible to overload [] operator twice? To allow, something like this: function[3][3] (like in a two dimensional array).
If it is possible, I would like to see some example code.
You can overload operator[] to return an object on which you can use operator[] again to get a result.
class ArrayOfArrays {
public:
ArrayOfArrays() {
_arrayofarrays = new int*[10];
for(int i = 0; i < 10; ++i)
_arrayofarrays[i] = new int[10];
}
class Proxy {
public:
Proxy(int* _array) : _array(_array) { }
int operator[](int index) {
return _array[index];
}
private:
int* _array;
};
Proxy operator[](int index) {
return Proxy(_arrayofarrays[index]);
}
private:
int** _arrayofarrays;
};
Then you can use it like:
ArrayOfArrays aoa;
aoa[3][5];
This is just a simple example, you'd want to add a bunch of bounds checking and stuff, but you get the idea.
An expression x[y][z] requires that x[y] evaluates to an object d that supports d[z] .
This means that x[y] should be an object with an operator[] that evaluates to a "proxy object" that also supports an operator[] .
This is the only way to chain them.
Alternatively, overload operator() to take multiple arguments, such that you might invoke myObject(x,y) .
It is possible if you return some kind of proxy class in first [] call. However, there is other option: you can overload operator() that can accept any number of arguments ( function(3,3) ).
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