Operators in C++

An operator is a symbol that tells the compiler to perform specific mathematical or logical manipulations. C++ is rich in built-in operators and provide the following types of operators −

• Arithmetic Operators
• Relational Operators
• Logical Operators
• Bitwise Operators
• Assignment Operators
• Misc Operators

This chapter will examine the arithmetic, relational, logical, bitwise, assignment and other operators one by one.

Arithmetic Operators

Arithmetic operators in C++ are the basic operators, which are used for basic mathematical or arithmetical operations on operands. These operators are essential for performing calculations and manipulating data within a program.

There are following arithmetic operators supported by C++ language −

Assume variable A holds 10 and variable B holds 20, then −

Example

The following is an example of arithmetic operators −

#include <iostream>
using namespace std;
 
main() {
   int a = 21;
   int b = 10;
   int c ;

   c = a + b;
   cout << "Line 1 - Value of c is :" << c << endl ;

   c = a - b;
   cout << "Line 2 - Value of c is  :" << c << endl;

   c = a * b;
   cout << "Line 3 - Value of c is :" << c << endl ;

   c = a / b;
   cout << "Line 4 - Value of c is  :" << c << endl ;

   c = a % b;
   cout << "Line 5 - Value of c is  :" << c << endl ;

   c = a++; 
   cout << "Line 6 - Value of c is :" << c << endl ;

   c = a--; 
   cout << "Line 7 - Value of c is  :" << c << endl ;

   return 0;
}

Output

Line 1 - Value of c is :31
Line 2 - Value of c is  :11
Line 3 - Value of c is :210
Line 4 - Value of c is  :2
Line 5 - Value of c is  :1
Line 6 - Value of c is :21
Line 7 - Value of c is  :22

Relational Operators

Relational operators are used to compare two values or expressions. These operators return a boolean value − true if the comparison is correct, and else false.

They are essential for making decisions and controlling the flow of a program based on conditions.

There are following relational operators supported by C++ language

Assume variable A holds 10 and variable B holds 20, then −

Example

The following is an example of relational operators −

#include <iostream>
using namespace std;

main() {
   int a = 21;
   int b = 10;
   int c ;

   if( a == b ) {
      cout << "Line 1 - a is equal to b" << endl ;
   } else {
      cout << "Line 1 - a is not equal to b" << endl ;
   }
   
   if( a < b ) {
      cout << "Line 2 - a is less than b" << endl ;
   } else {
      cout << "Line 2 - a is not less than b" << endl ;
   }
   
   if( a > b ) {
      cout << "Line 3 - a is greater than b" << endl ;
   } else {
      cout << "Line 3 - a is not greater than b" << endl ;
   }
   
   /* Let's change the values of a and b */
   a = 5;
   b = 20;
   if( a <= b ) {
      cout << "Line 4 - a is either less than \ or equal to  b" << endl ;
   }
   
   if( b >= a ) {
      cout << "Line 5 - b is either greater than \ or equal to b" << endl ;
   }
   
   return 0;
}

Output

Line 1 - a is not equal to b
Line 2 - a is not less than b
Line 3 - a is greater than b
Line 4 - a is either less than  or equal to  b
Line 5 - b is either greater than  or equal to b

Logical Operators

Logical operators are used to perform logical operations on boolean values (true or false). These operators are essential for controlling the flow of a program based on conditions. There are three primary logical operators in C++ as mentioned below −

There are following logical operators supported by C++ language.

Assume variable A holds 1 and variable B holds 0, then −

Example

The following is an example of logical operators −

#include <iostream>
using namespace std;

main() {
   int a = 5;
   int b = 20;
   int c ;

   if(a && b) {
      cout << "Line 1 - Condition is true"<< endl ;
   }
   
   if(a || b) {
      cout << "Line 2 - Condition is true"<< endl ;
   }
   
   /* Let's change the values of  a and b */
   a = 0;
   b = 10;
   
   if(a && b) {
      cout << "Line 3 - Condition is true"<< endl ;
   } else {
      cout << "Line 4 - Condition is not true"<< endl ;
   }
   
   if(!(a && b)) {
      cout << "Line 5 - Condition is true"<< endl ;
   }
   
   return 0;
}

Output

Line 1 - Condition is true
Line 2 - Condition is true
Line 4 - Condition is not true
Line 5 - Condition is true

Bitwise Operators

Bitwise operators are used to perform operations at the bit level on integer data types. These operations work on direct manipulation of bits, such as low-level programming, graphics, and cryptography.

Bitwise operator works on bits and perform bit-by-bit operation. The truth tables for &, |, and ^ are as follows −

Assume if A = 60; and B = 13; now in binary format they will be as follows −

A = 0011 1100

B = 0000 1101

-----------------

A&B = 0000 1100

A|B = 0011 1101

A^B = 0011 0001

~A = 1100 0011

The Bitwise operators supported by C++ language are listed in the following table. Assume variable A holds 60 and variable B holds 13, then −

Example

The following is an example of bitwise operators −

#include <iostream>
using namespace std;

main() {
   unsigned int a = 60;	  // 60 = 0011 1100  
   unsigned int b = 13;	  // 13 = 0000 1101
   int c = 0;           

   c = a & b;             // 12 = 0000 1100
   cout << "Line 1 - Value of c is : " << c << endl ;

   c = a | b;             // 61 = 0011 1101
   cout << "Line 2 - Value of c is: " << c << endl ;

   c = a ^ b;             // 49 = 0011 0001
   cout << "Line 3 - Value of c is: " << c << endl ;

   c = ~a;                // -61 = 1100 0011
   cout << "Line 4 - Value of c is: " << c << endl ;

   c = a << 2;            // 240 = 1111 0000
   cout << "Line 5 - Value of c is: " << c << endl ;

   c = a >> 2;            // 15 = 0000 1111
   cout << "Line 6 - Value of c is: " << c << endl ;

   return 0;
}

Output

Line 1 - Value of c is : 12
Line 2 - Value of c is: 61
Line 3 - Value of c is: 49
Line 4 - Value of c is: -61
Line 5 - Value of c is: 240
Line 6 - Value of c is: 15

Assignment Operators

Assignment operators are used to assign values to variables. These operators allow you to set or update the value stored in a variable.

There are following assignment operators supported by C++ language −

Example

The following is an example of assignment operators −

#include <iostream>
using namespace std;

main() {
   int a = 21;
   int c ;

   c =  a;
   cout << "Line 1 - =  Operator, Value of c = : " <<c<< endl ;

   c +=  a;
   cout << "Line 2 - += Operator, Value of c = : " <<c<< endl ;

   c -=  a;
   cout << "Line 3 - -= Operator, Value of c = : " <<c<< endl ;

   c *=  a;
   cout << "Line 4 - *= Operator, Value of c = : " <<c<< endl ;

   c /=  a;
   cout << "Line 5 - /= Operator, Value of c = : " <<c<< endl ;

   c  = 200;
   c %=  a;
   cout << "Line 6 - %= Operator, Value of c = : " <<c<< endl ;

   c <<=  2;
   cout << "Line 7 - <<= Operator, Value of c = : " <<c<< endl ;

   c >>=  2;
   cout << "Line 8 - >>= Operator, Value of c = : " <<c<< endl ;

   c &=  2;
   cout << "Line 9 - &= Operator, Value of c = : " <<c<< endl ;

   c ^=  2;
   cout << "Line 10 - ^= Operator, Value of c = : " <<c<< endl ;

   c |=  2;
   cout << "Line 11 - |= Operator, Value of c = : " <<c<< endl ;

   return 0;
}

Output

Line 1 - =  Operator, Value of c = : 21
Line 2 - += Operator, Value of c = : 42
Line 3 - -= Operator, Value of c = : 21
Line 4 - *= Operator, Value of c = : 441
Line 5 - /= Operator, Value of c = : 21
Line 6 - %= Operator, Value of c = : 11
Line 7 - <<= Operator, Value of c = : 44
Line 8 - >>= Operator, Value of c = : 11
Line 9 - &= Operator, Value of c = : 2
Line 10 - ^= Operator, Value of c = : 0
Line 11 - |= Operator, Value of c = : 2

Misc Operators

Miscellaneous operators, often abbreviated as “misc operators”, include a variety of operators that don’t fit neatly into other categories like arithmetic or logical operators. Here are some common miscellaneous operators and their definitions −

The following table lists some other operators that C++ supports.

Conditional (Ternary) Operator (?:)

It is a shorthand way to perform a conditional evaluation in C++.

int a = 10, b = 20;
int result = (a > b) ? a : b;  // result will be 20 because a is not greater than b
cout << "The greater value is: " << result << endl;

Output

The greater value is: 20

Sizeof Operator

The sizeof operator returns the size, in bytes, of a variable or data type.

int x = 5;
cout << "Size of int: " << sizeof(x) << " bytes" << endl;  
cout << "Size of double: " << sizeof(double) << " bytes" << endl;

Output

4
8

Bitwise Complement Operator (~)

The bitwise complement operator inverts the bits of its operand.

unsigned int num = 5;  // Binary: 00000000 00000000 00000000 00000101
unsigned int result = ~num;  // Binary: 11111111 11111111 11111111 11111010
cout << "Bitwise complement of 5: " << result << endl;  // Outputs a large positive number due to unsigned

Scope Resolution Operator (::)

This operator is used to define the scope of a function or variable, particularly in the context of classes and namespaces.

class MyClass {
public:
    static int value;
};

int MyClass::value = 10;  // Define static member outside the class

cout << "Static value: " << MyClass::value << endl;

Output

10

Operators Precedence in C++

Operator precedence determines the grouping of terms in an expression. This affects how an expression is evaluated. Certain operators have higher precedence than others; for example, the multiplication operator has higher precedence than the addition operator −

For example x = 7 + 3 * 2; here, x is assigned 13, not 20 because operator * has higher precedence than +, so it first gets multiplied with 3*2 and then adds into 7.

Here, operators with the highest precedence appear at the top of the table, those with the lowest appear at the bottom. Within an expression, higher precedence operators will be evaluated first.

Example

The following is an example of demonstrating operators precedence −

#include <iostream>
using namespace std;
 
main() {
   int a = 20;
   int b = 10;
   int c = 15;
   int d = 5;
   int e;

   e = (a + b) * c / d;      // ( 30 * 15 ) / 5
   cout << "Value of (a + b) * c / d is :" << e << endl ;

   e = ((a + b) * c) / d;    // (30 * 15 ) / 5
   cout << "Value of ((a + b) * c) / d is  :" << e << endl ;

   e = (a + b) * (c / d);   // (30) * (15/5)
   cout << "Value of (a + b) * (c / d) is  :" << e << endl ;

   e = a + (b * c) / d;     //  20 + (150/5)
   cout << "Value of a + (b * c) / d is  :" << e << endl ;
  
   return 0;
}

Output

Value of (a + b) * c / d is :90
Value of ((a + b) * c) / d is  :90
Value of (a + b) * (c / d) is  :90
Value of a + (b * c) / d is  :50