C++ LANGUAGE subscripting[] operator overloading

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C++ LANGUAGE subscripting[] operator overloading

Subscripting [ ] Operator Overloading 


The subscript operator [] is normally used to access 
array elements. This operator can be overloaded to 
enhance the existing functionality of C++ arrays. 

Following example explains how a subscript operator [] can be overloaded. 

#include <iostream> 
using namespace std; 
const int SIZE = 10; 
 
class safearay 
{ 
   private: 
      int arr[SIZE]; 
   public: 
      safearay()  
      { 
         register int i; 
         for(i = 0; i < SIZE; i++) 
         { 
           arr[i] = i; 
         } 
      } 
      int &operator[](int i) 
      { 
          if( i > SIZE ) 
          { 
              cout << "Index out of bounds" <<endl;  
              // return first element. 
              return arr[0]; 
          } 
          return arr[i]; 
      } 
}; 
int main() 
{ 
   safearay A; 
 
   cout << "Value of A[2] : " << A[2] <<endl; 
   cout << "Value of A[5] : " << A[5]<<endl; 
   cout << "Value of A[12] : " << A[12]<<endl; 
 
   return 0; 
} 
When the above code is compiled and executed, it produces the following result: 
Value of A[2] : 2 
Value of A[5] : 5 
Index out of bounds 
Value of A[12] : 0