Overloading array index operator [] in C++

Operator overloading has an important role in object oriented programming language features. Operator overloading is a type of compile time or static polymorphism.

Algorithm

Begin
   Create a class Arr and declare size of array.
   Inside the class, initialize all the elements by using for loop.
   Print the all elements.
End.

Example Code

 Live Demo

#include <iostream>
#include <stdlib.h>
using namespace std;
const int M = 7;
class Arr {
   private:
   int A[M];
   int size;
   public:
   Arr(int s, int v) {
      if(s>M) {
         cout<<endl<<"This is beyond maximum size";
         exit(1);
      }
      size = s;
      for(int i=0;i<size;i++)
         A[i] = v;
   }
   int& operator[](int i) {
      if( (i<0) || (i>=size) ) {
         cout<<endl<<"Error: Array out of bound";
         exit(1);
      }
      return A[i];
   }
};
int main() {
   int i=0;
   Arr a(7,0);
   for(i=0;i<7;i++)
      a[i] = i*10;
   cout<<"Array elements are:"<<endl;
   for(i=0;i<7;i++) {
      int val = a[i];
      cout<<val<<endl;
   }
   return 0;
}

Output

Array elements are:
0
10
20
30
40
50
60