C++ Operators

In C++ programming, operators are used to perform operations on operands (i.e. variables and values).

C++ categorizes the operators in the following groups:

1. Arithmetic operators
2. Assignment operators
3. Relational operators
4. Logical operators
5. Bit-wise operators
6. Conditional Operators

Finally, miscellaneous operators such as sizeof, cast, member, and pointer are discussed here. 

1. Arithmetic Operators

These operators are used with numeric values to perform common mathematical operations.​

Example 1

//arithmetic.cpp
#include 
using namespace std;

int main() {
   int a = 100;
   int b = 5;
   int c, d;

   //arithmetic operators demo
   cout << "ADD: " << (a + b) << endl;
   cout << "SUB: " << (a - b) << endl;
   cout << "MUL: " << (a * b) << endl;
   cout << "DIV: " << (a / b) << endl;
   cout << "MOD: " << (a % b) << endl;

   //post increment or decrement
   c = b++; d = b--;
   cout << "Post ++: " << c << endl;
   cout << "Post --: " << d << endl;

   //pre increment or decrement
   c = ++b; d = --b;
   cout << "Pre ++: " << c << endl;
   cout << "Pre --: " << d << endl;

  return 0; 
}

Output:

ADD: 105
SUB: 95
MUL: 500
DIV: 20
MOD: 0
Post ++: 5
Post --: 6
Pre ++: 6
Pre --: 5

2. Assignment Operators

These operators are used to assign values to variables.

Example 2

//assignment.cpp
#include 
using namespace std;

int main() {
   int x = 5;

   //assignment operators demo 
   x = x + 5;  // x += 5
   cout << "x = " << x << endl;
   x = x - 5;  // x -= 5
   cout << "x = " << x << endl;
   x = x * 5;  // x *= 5
   cout << "x = " << x << endl;
   x = x / 5;  // x /= 5
   cout << "x = " << x << endl;
   x = x % 5;  // x %= 5
   cout << "x = " << x << endl;

   return 0; 
}

Output:

x = 10
x = 5
x = 25
x = 5
x = 0

3. Relational Operators

These operators are used to compare two values.

Example 3

//relational.cpp
#include 
using namespace std;

int main() {
   int a = 10, b = 5;

   //relational operators demo 
   cout << (a>b) << endl;  //1
   cout << (a<b) << endl;  //0
   cout << (a==b) << endl; //0
   cout << (a!=b) << endl; //1
   cout << (a>=b) << endl; //1
   cout << (a<=b) << endl; //0

   return 0; 
}

Output:

1
0
0
1
1
0

4. Logical Operators

These operators are used to combine conditional statements.

Example 4

//logical.cpp
#include 
using namespace std;

int main() {
int result;

   //logical operators demo 
   result = ((10>5) && (9<7));
   cout << "Logical AND = " << result << endl; //0
   result = ((10>5) || (9<7));
   cout << "Logical OR = " << result << endl; //1
   result = !(9<7);
   cout << "Logical NOT = " << result << endl; //1

   return 0; 
}

Output:

Logical AND = 0
Logical  OR = 1
Logical NOT = 1

5. Bit-wise Operators

These operators are used to compare binary numbers.

For example, in the table below, let x = 10 (0000 1010 in binary) and y = 4 (0000 0100 in binary)

Example 5

//bitwise.cpp
#include 
using namespace std;

int main() {
   int x = 10;
   int y = 4;

   //bitwise operators demo 
   cout << "Bit-wise AND: " << (x & y) << endl; //0
   cout << "Bit-wise OR: " << (x | y) << endl;  //14
   cout << "Bit-wise NOT: " << (~x) << endl;    //-11
   cout << "Bit-wise XOR: " << (x ^ y) << endl; //14
   cout << "Bit-wise right shift: " << (x >> 2) << endl; //2
   cout << "Bit-wise left shift: " << (x << 2) << endl;  //40

   return 0; 
}

Output:

Bit-wise AND: 0
Bit-wise  OR: 14
Bit-wise NOT: -11
Bit-wise XOR: 14
Bit-wise right shift: 2
Bit-wise  left shift: 40

6. Conditional Operators

The conditional operator is the only ternary operator (operator that takes three arguments) in C++. The operator evaluates the first argument and, if true, evaluates the second argument. If the first argument evaluates to false, then the third argument is evaluated. The conditional operator is the expression equivalent of the if-else statement.

Example 6

//conditional.cpp
#include 
using namespace std;

int main() {
   int a = 15, b = 12;
   int result;

   //conditional operators demo 
   result = a > b ? 1 : 0;
   cout << "Result = " << result << endl; //1

   return 0; 
}

Output:

Result = 1

Miscellaneous Operators

The following text describes some other operators supported by C++ language.

sizeof operator: The sizeof is a compile-time operator that determines the size, in bytes, of a variable or data type. An example is given below:

int a = 10 ;
//sizeof operator
cout << sizeof(a) << endl;       //4
cout << sizeof(double) << endl;  //8

cast operator: A cast is a unary operator that converts one data type into another. An example is given below:

float f = 10.25;
int i ;
//casting operator
i = (int) f;  
cout << i; //10

member operators: The . (dot) operator and the -> (arrow) operator are the member operators which are used to refer individual members of classes, structures, and unions. We will explain this topic later with respect to C++ structures.

pointer operators: C++ provides two pointer operators, which are –

(i) address of operator & and

(ii) Indirection operator *.

We will explain this topic later with respect to C++ pointers.