Operator Overloading in C++ with examples

What is Operator overloading?

 In C++, it may possibly add particular options to the performance and behavior of already present operators like athematic and different operations. The mechanism of giving particular that means to an operator is called operator overloading. For instance, we are able to overload an operator ‘+’ in a class-like string to concatenate two strings by simply utilizing +. 

Operations that may be carried out:

• Athematic operations: + – * / %
• Logical operations:  && and ||
• Relational operations: == != >= <=
• Pointer operators: & and *
• Memory administration operator: new, delete []

Implementing Operator overloading:

• Member operate: It is within the scope of the category during which it’s declared.
• Friend operate: It is a non-member operate of a category with permission to entry each non-public and guarded members. 

Operator Overloading Examples

Example 1: Let us multiply two fractions utilizing the overloading of the multiplication operator in C++.

// Multiplication of two fractions
#embrace <iostream>
utilizing namespace std;

class Frac {
   non-public:
    int a;
    int b;

   public:
    Frac() : a(0), b(0) {}

    void in() {
        cout << "Enter the numerator : ";
        cin >> a;
        cout<< "Enter the denominator : ";
        cin >> b;
    }

    // Overload the * operator
    Frac operator * (const Frac &obj) {
        Frac temp;
        temp.a = a * obj.a;
        temp.b = b * obj.b;
       
        return temp;
    }

    void out() {
      cout<<"The fraction is  "<< a<<"/ "<<b;
    }
};

int essential() {
    Frac F1, F2, outcome;

    cout << "Enter the primary fraction:n";
    F1.in();

    cout << "Enter the second fraction:n";
    F2.in();

   // complex1 calls the operator operate
   // complex2 is handed as an argument to the operate
    outcome = F1 * F2;
    outcome.out();

    return 0;
}

OutPut
Enter the primary fraction:
Enter the numerator : 2
Enter the denominator : 5 
Enter the second fraction:
ENter the numerator: 12
Enter the denominator: 7
The fraction is 24/35

Example 2: A C++ program to overload a prefix decrement operator

#embrace <iostream>
utilizing namespace std;

class OverLoad {
   non-public:
    int a;
    int b;

   public:
    OverLoad() : a(0), b(0) {}

    void in() {
        cout << "Enter the primary quantity : ";
        cin >> a;
        cout<< "Enter the second quantity : ";
        cin >> b;
    }

    // Overload the prefix decrement operator
    void operator-- () {
        a= --a;
        b= --b;
    }

    void out() {
      cout<<"The decremented components of the article are:  "<<endl<< a<<" and " <<b;
    }
};

int essential() {
    OverLoad obj;
    obj.in();
    --obj;
    obj.out();

    return 0;
}

Output
Enter the primary quantity : 56 
ENter the second quantity : 234 
The decremented components fo the objects are: 55 and 223

Example 3: Overloading a NOT (!) operator

#embrace <iostream>
utilizing namespace std;

class NotOp {
   non-public:
    int a;
    bool b;

   public:
    NotOp() : a(0), b(true) {}

    void in() {
        cout << "Enter the primary quantity : ";
        cin >> a;
        cout<< "Enter true or false : ";
        cin >> b;
    }

    // Overloading the NOT (!)  operator
    void operator ! () {
        a= !a;
        b= !b;
    }

    void out() {
      cout<<"Output: "<<endl<< a<<endl<<b;
    }
};

int essential() {
    NotOp obj;
    !obj;
    obj.out();

    return 0;
}

Output 
1
0

Difference between Member and pal operate

Member operate:

1. The variety of parameters to be handed is diminished by one, because the calling object is implicitly equipped is an operand.
2. Unary operators tales no express parameters.
3. Binary operators take just one express parameter.

Friend Function:

1. More parameters may be handed.
2. Unary operators take one express parameter.
3. Binary operators take two express parameters.

What are the principles for operator overloading in C++?

1. To work, at the least one of many operands should be a user-defined class object.
2. We can solely overload the prevailing operators, Can’t overload new operators.
3. Some operators can’t be overloaded utilizing a pal operate. However, such operators may be overloaded utilizing the member operate.

Which operators Cannot be overloaded?

1. Conditional [?:], dimension of, scope(::), Member selector(.), member pointer selector(.*) and the casting operators.
2. We can solely overload the operators that exist and can’t create new operators or rename present operators.
3. At least one of many operands in overloaded operators should be user-defined, which implies we can not overload the minus operator to work with one integer and one double. However, you would overload the minus operator to work with an integer and a mystring.
4.  It will not be attainable to vary the variety of operands of an operator helps.
5. All operators preserve their default priority and associations (what they use for), which can’t be modified.
6. Only built-in operators may be overloaded.

Advantages of an operator overloading in C++

1. Operator overloading in c++ allows programmers to make use of notation nearer to the goal area.
2. They present related help to built-in varieties of user-defined sorts.
3. Operator overloading in c++ makes this system simpler to grasp.

Disadvantages of an operator overloading in C++

In operator overloading, any C++ present operations may be overloaded, however some exceptions.

The want for operator overloading in C++

It permits us to offer an intuitive interface to our class customers, plus makes it attainable for templates to work equally effectively with lessons and built-in sorts. Operator overloading permits C++ operators to have user-defined meanings on user-defined sorts or lessons.

The syntax for operator overloading:

Class class_name
	{
  		………………….
		…………………..
	Public 
		Return_type operator image (argument ())
		{
			……………….
			……………….
		}
	………………………….
};

Unary Operators and Binary Operator overloading

Unary operators:

• Operators which work on a single operand are known as unary operators.
• Examples: Increment operators(++), Decrement operators(–),unary minus operator(-), Logical not operator(!) and many others…

Binary operators:

• Operators which works on Two operands are known as binary operator.

Operator Overloading in Unary Operators

We can overload a unary operator like some other operator. We can redefine the unary operators to behave in a sure means on sure operands utilizing unary operator overloading in C++. It is mainly used for working on user-defined datatypes, like lessons and constructions.

Example: Let us strive overloading the increment and decrement operators by means of a C++ program.

#embrace<iostream>
utilizing namespace std;

class UnaryOverload
{
        int hr, min;
     public:
        void in()
        {
                cout<<"n Enter the time: n";
                cin>>hr;
                cout<<endl;
                cin>>min;
        }
        void operator++(int) //Overload Unary Increment
        {
                hr++;
                min++;
        }
        void operator--(int) //Overload Unary Decrement
        {
                hr--;
                min--;
        }
        
        void out()
        {
                cout<<"nTime is "<<hr<<"hr "<<min<<"min";
               
        }
};
int essential()
{
        UnaryOverload ob;
        ob.in();
        ob++;
        cout<<"nn After Incrementing : ";
        ob.out();
        ob--;
        ob--;
        cout<<"nn After Decrementing : ";
        ob.out();
        return 0;
}

Output
Enter the time: 
5
56
After Incrementing:
Time is 6hr 57 minutes
After Decrementing:
Time is 4hr 55 min

Operator Overloading in Binary Operators

We can redefine the binary operators to function in a sure means for user-defined objects. The binary operators are the operators that work on two operands, akin to addition (+), multiplication (*), and many others. A single operator can perform a wide range of functionalities utilizing two operands supplied by the programmer or consumer on this polymorphic compile method.

Example: Let us see the next C++ code that elaborates the overloading of the addition operator.

#embrace <iostream>
utilizing namespace std;

class Time {
   non-public:
    int hour;
    int minute;

   public:
    Time() : hour(0), minute(0) {}

    void in() {
        cout << "Enter the time: ";
        cin >> hour;
        cin >> minute;
    }

    // Overload the + operator
    Time operator + (const Time & obj) {
        Time temp;
        temp.hour = hour + obj.hour;
        temp.minute = minute + obj.minute;
        if (temp.minute>=60)
        {
            temp.hour+=1;
            temp.minute-=60;
        }
        if (temp.hour>24)
        temp.hour=1;
        return temp;
    }

    void out() {
      cout<<"Time is "<< hour<<"hrs "<<minute<<"min";
    }
};

int essential() {
    Time T1, T2, outcome;

    cout << "Enter first time in hours and minutes one after the other :n";
    T1.in();

    cout << "Enter second time in hours and minutes one after the other :n";
    T2.in();

   // T1 calls the operator operate
   // T2 is handed as an argument to the operate
    outcome = T1 + T2;
    outcome.out();

    return 0;
}

Output
Enter first time in hours and minutes one after the other:
Enter the time:11
56
Enter second time in hours and minutes one after the other:
Enter the time: 2
10
Time is 14hrs 6 min

Overloadable/Non-overloadable Operators

Now that you simply noticed the overloading of unary and binary operators in C++ within the earlier sections of this weblog, you will need to know that not all operators may be overloaded. The operators that may be overloaded in C++ are often known as overloadable operators. However, there are some non-overloadable operators as effectively that may’t be overloaded. 

The checklist of non-overloadable operators goes as follows:

• Ternary operator (? 🙂
• Dot operator or member entry operator (.)
• Pointer to member operator (.*)
• Scope decision operator ( :: )
• Object kind operator (typeid)
• Object dimension operator (sizeof)

These operators can’t be overloaded as a result of doing so will trigger vital programming issues. As an illustration, the sizeof operator returns the operand, which is the scale of the article or datatype. The compiler evaluates this. It can’t be assessed in real-time. We can’t thus overburden it.

Overloading particular operators in C++

Some of the particular operators in C++ are as follows:

1. new – It is used to allocate the reminiscence dynamically.
2. Delete – It is used to free the reminiscence dynamically.
3. [] – It is a subscript operator.
4. -> – – It is a member entry operators.
5. = – It is used to assign the values.
6. () – It is used for operate name.

The operators apart from listed above may be overloaded both as a member or as non-members. But usually, non-member overloading is advisable. Because:

1. Symmetry: When a binary operator is outlined as a category technique, it will need to have objects as its operands. We ought to write like advanced*5 however not like 5*advanced as a result of 5. operator*(advanced)doesn’t make any sense. In different phrases, a*b ought to be the identical as b*a. Otherwise, it breaks the cumulativeness that the consumer is anticipating from the *operator. So, on this case, we should always use no-member operators overloading.
2. Weak coupling: since a non-member technique can not entry non-public member, it tends to make the category much less coupled

Example:

Using unary operator:
 //Overload ++ when used as prefix
#embrace<iostream.h>
Using namespace std;
Class depend
{ 
 Private:
 Int worth;
 Public:
//constructor to initialize depend to five
Count() : worth(5)  {}
//overload ++ when used as prefix
Void operator ++ () 
{ 
++worth;
}
Void show()
{
Cout<<”Count: “<<worth<<endl;
}
};
Int essential()
{
Count count1;
//name the “void operator ++ ()” operate
++count1:
Count1.show();
Return 0;
}

Output 
Count:  6

NOTE: 
Here, When we use ++count1; , the void operator ++() is known as. 
This will increase the worth attribute for the article depend 1 by 1.
When we overload the operators, we are able to use them to work in any means we like. For instance, we might have used ++ to extend the worth by 100.
However, this makes our code extra complicated and obscure. So utilizing operators in overloading accurately and persistently, and understandably helps straightforward to grasp with none difficulties.
The above-given instance works when ++ is used as a prefix to make ++ works as a postfix; we use this syntax.
Syntax:
Here, the int contained in the parentheses. It’s the syntax used for utilizing unary operators as postfix; it’s not a operate parameter.

Example 2: 

//C++ program to overload the binary operator +
//This program provides two advanced numbers

#embrace<iostream.h>
utilizing namespace std;
 class Complex
{
 Private:
  float actual;
 float imag;
Public:
//constructor to initialize actual and imag to 0
Complex() :  actual(0), picture(0)  {}
 void enter()
{
 // overload the + operator
Complex operator + (const Complex7 obj)
{
Complex temp;
temp.actual = actual +obj.actual;
temp.imag = imag +obj.imag;
return temp;
}

void output()
{
If(imag<0)
 Cout<< “OutputComplex number: ” << actual << “i”;
else
depend<< “Output Complex number: “<< “+” << “I”;
}
};
Int essential()
{
Complex complex1, complex2,outcome;
Cout<< “Enter first advanced quantity:n;
Complex1.enter();
Cout<< “Enter second complex number:n”;
Complex2.enter();

//complex1 calls the operator operate
//complex2cis handed as an arguments to the operate
outcome = complex1 + complex2;
outcome.output();
}

Output:
Enter a primary advanced quantity:
Enter actual and imaginary elements respectively: 9 5
Enter a second advanced quantity:
Enter actual and imaginary elements respectively: 7 ^
Output Complex quantity: 16+11i

In this program, the operator operate is:

Complex operator + (const Complex7 obj)

We may write this operate like:

Complex operator + (Complex  obj)
{
//code
}

Access specifiers

Every member of a category is specified by 3 ranges of entry safety. These are used to outline the scope of members of a category.

The entry specifiers are indicated by utilizing the key phrases:

1. Private: Private entry means member knowledge written underneath this part is accessible by solely member capabilities. They can’t be accessed from exterior the category or anyplace in this system. If no entry specifiers are talked about, then by default, members are handled as non-public.
2. Public: It implies that members may be accessed by any operate inside or exterior the category, however inside a program. The non-public variable peak is accessed by means of the member operate. Some of the general public operate of a category supplies an interface for accessing the non-public and guarded class members.
3. Protected: The class members of this part are accessible by the member capabilities of the identical class, associates of the category, and member capabilities derived from this class. The members can’t be accessed from exterior; It is much like the non-public members.

Operator Overloading in C++ FAQs

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