Operator overloading: Array indexing [] – allow for double indexing [][]
I'm not sure how to overload the operator[] for double indexing. Please help if you can. Thanks
You have not mentioned the language with which you are working. Since Java does not allow operator overloading, I assume you are working with C++. It would be nice to mention "Programming C++" or something similar in your subject.
Back to arrays. Native C++ already allows double array indexing. Something like the following already works as is, without additional code.
int a[4][4];
for(int i=0;i<4;i++)for(int j=0;j<4;j++)...
If you want to know more about operator overloading in general, you can read up textbooks, or tutorials such as:
http://www.deitel.com/articles/cplusplus_tutorials/20060204/
To overload the `operator[]` for double indexing, you can define a nested class within your main class that represents the inner array. This nested class should also overload the `operator[]`. Here's a step-by-step explanation of how to achieve this:
Step 1: Define the main class
The main class represents the outer array and will be responsible for creating and managing the inner arrays. You need to define a private member variable of the nested class type to store the inner arrays.
```cpp
class DoubleIndexArray {
private:
// Define private member variable to store inner arrays
// For simplicity, let's assume each inner array has size 10
InnerArray innerArrays[10];
public:
// Constructor
DoubleIndexArray() {
// Initialize inner arrays if needed
for (int i = 0; i < 10; i++) {
// For simplicity, let's assume inner arrays are already initialized
}
}
// Return the inner array at the specified index
InnerArray& operator[](int index) {
// Return the inner array at the specified index
return innerArrays[index];
}
};
```
Step 2: Define the nested class
The nested class represents the inner array. You need to define a private member variable to store the elements of the inner array, and then overload the `operator[]` within this class.
```cpp
class DoubleIndexArray {
private:
class InnerArray {
private:
// Define private member variable to store elements of the inner array
int elements[10];
public:
// Return the element at the specified index in the inner array
int& operator[](int index) {
// Return the element at the specified index in the inner array
return elements[index];
}
};
// Define private member variable to store inner arrays
InnerArray innerArrays[10];
public:
// Constructor and outer array indexing implementation omitted for brevity
};
```
Step 3: Using double indexing
Now you can use double indexing on objects of the `DoubleIndexArray` class. For example:
```cpp
DoubleIndexArray myArray;
myArray[0][0] = 42; // Access element at index [0][0]
int value = myArray[1][2]; // Access element at index [1][2]
```
This will allow you to access elements in the outer array using the first set of square brackets, and then access elements within the selected inner array using the second set of square brackets.