operator overloading in c++

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Operator overloading

Hi guys can some one please suggest a good tutorial on operator overloading?
I was going through this code on operator overloading and I have the following doubts
code:

#include <iostream>
using namespace std;
class Array {

 int *a;
 int size;
 int capacity;

 public:
    Array (int c) {a=new int[c]; size=0; capacity =c; } ;
    Array & operator <<  (int x); 
    int  operator []  (int i) { 
        if (i<size) return a[i] ;
        else  {
            cout <<"Segmentation Fault Prevented!n"; 
            return -1;
        }
    };
};
Array &Array::operator <<  (int x) { 
   if (size < capacity) a[size++] = x;
   else {
    int *tmp = new int[size+capacity];
    for (int j=0; j<size; j++)
        tmp[j]=a[j];
    delete [] a;
    a = tmp;
    a[size++]=x;
    capacity=size+capacity;
   }
   return *this;

} ; 

int main (int agrc, char *argv[] ) {

 Array b(10);

    for (int i=0; i<100; i++) b << i;
    b << 1 << 2 << 3;
    for (int i=0; i<105; i++) cout << b[i] << endl;
}

I have these doubts:

Can some one please suggest a good tutorial on operator overloading?

what does Array & operator << (int x); mean?

int operator [] (int i) - if this is a function why are we putting square brackets here?

Array &Array::operator means what?

what is *this ?

Please help me...I am new to c++ so have these doubts.... Thanks in advance

---

Google is your friend :) or have a look at http://www.parashift.com/c++-faq-lite/operator-overloading.html

It overloads the << operator

It overloads the [] operator, so you can use yourobject[something] . It's used eg by std::map

It looks like the beginning of the implementation of an overloaded operator.

It's a reference to the current object.

---

Answer to (1): Did you look at the FAQ? http://www.parashift.com/c++-faq-lite/operator-overloading.html

---

Everytime you encount T operatorX , where X can be any of (),[],<<,>>,+,+=,=,--,++ etc., that's what is called "operator overloading". It does just what it says -- it enables you to use that operator on the class it's overloaded for. For example your array could be accessed like this:

Array myArr(10);
myArr[0] == 5;
myArr[1] == 10;
//   ^^^ --- this is using the `operator[]` with an int parameter

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