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C++ Operators

Computer Science / C++ tutorial chapter - Published 2025-12-13 - C++

An operator is a symbol that acts on a value to perform specific mathematical or logical operations, forming the core of any programming language. In C++, a range of built-in operators is available to perform essential tasks and calculations.

Example:

c = a + b;

In this example, the + symbol is the addition operator, while a and b are the operands. The addition operator tells the compiler to sum the values of a and b.

Types of Operators in C

The C language provides a wide array of operators, categorized into six types:

1. Arithmetic Operators
2. Relational Operators
3. Logical Operators
4. Bitwise Operators
5. Assignment Operators
6. Miscellaneous Operators

1. Arithmetic Operators in C : Arithmetic operators allow us to perform standard mathematical operations. In C, there are 9 arithmetic operators:

C++ Operators
Symbol	Operator	Description	Syntax
`+`	Addition	Adds two numeric values.	`a + b`
`-`	Subtraction	Subtracts the right operand from the left.	`a - b`
`*`	Multiplication	Multiplies two numeric values.	`a * b`
`/`	Division	Divides two numeric values.	`a / b`
`%`	Modulus	Gives the remainder of a division.	`a % b`
`+`	Unary Plus	Specifies positive values.	`+a`
`-`	Unary Minus	Reverses the sign of a value.	`-a`
`++`	Increment	Increases the value of a variable by 1.	`a++`
`--`	Decrement	Decreases the value of a variable by 1.	`a--`

Example:

#include <stdio.h>

int main() {
    int a = 25, b = 5;

    printf("a + b = %d\n", a + b);
    printf("a - b = %d\n", a - b);
    printf("a * b = %d\n", a * b);
    printf("a / b = %d\n", a / b);
    printf("a %% b = %d\n", a % b);
    printf("+a = %d\n", +a);
    printf("-a = %d\n", -a);
    printf("a++ = %d\n", a++);
    printf("a-- = %d\n", a--);

    return 0;
}

Output:

a + b = 30
a - b = 20
a * b = 125
a / b = 5
a % b = 0
+a = 25
-a = -25
a++ = 25
a-- = 26

2. Relational Operators in C : Relational operators are used to compare two operands. These operators return a boolean value (true or false), depending on the comparison result.

C++ Operators
Symbol	Operator	Description	Syntax
`<`	Less than	Returns true if the left operand is less than the right.	`a < b`
`>`	Greater than	Returns true if the left operand is greater than the right.	`a > b`
`<=`	Less than or equal to	Returns true if the left operand is less than or equal to the right.	`a <= b`
`>=`	Greater than or equal to	Returns true if the left operand is greater than or equal to the right.	`a >= b`
`==`	Equal to	Returns true if both operands are equal.	`a == b`
`!=`	Not equal to	Returns true if the operands are not equal.	`a != b`

Example:

#include <stdio.h>

int main() {
    int a = 25, b = 5;

    printf("a < b  : %d\n", a < b);
    printf("a > b  : %d\n", a > b);
    printf("a <= b: %d\n", a <= b);
    printf("a >= b: %d\n", a >= b);
    printf("a == b: %d\n", a == b);
    printf("a != b : %d\n", a != b);

    return 0;
}

Output:

a < b  : 0
a > b  : 1
a <= b: 0
a >= b: 1
a == b: 0
a != b : 1

3. Logical Operators in C : Logical operators are used to combine multiple conditions. They evaluate to a boolean value (true or false).

C++ Operators
Symbol	Operator	Description	Syntax
`&&`	Logical AND	Returns true if both operands are true.	`a && b`
`		`	Logical OR
`!`	Logical NOT	Returns true if the operand is false.	`!a`

Example:

#include <stdio.h>

int main() {
    int a = 25, b = 5;

    printf("a && b : %d\n", a && b);
    printf("a || b : %d\n", a || b);
    printf("!a: %d\n", !a);

    return 0;
}

Output:

a && b : 1
a || b : 1
!a: 0

The `sizeof` Operator in C++

The sizeof operator is a unary operator used during compilation to determine the size of variables, data types, constants, classes, structures, and unions in bytes.

Syntax:

sizeof(data_type)

Example 1:

The following program shows how to use sizeof to find the size of various data types.

#include <iostream>
using namespace std;

int main()
{
    cout << "Bytes taken up by short is " << sizeof(short) << endl;
    cout << "Bytes taken up by long long is " << sizeof(long long) << endl;
    cout << "Bytes taken up by bool is " << sizeof(bool) << endl;
    cout << "Bytes taken up by wchar_t is " << sizeof(wchar_t) << endl;
    return 0;
}

Output:

Bytes taken up by short is 2
Bytes taken up by long long is 8
Bytes taken up by bool is 1
Bytes taken up by wchar_t is 4

Example 2:

This example demonstrates the size of variables of different data types using the sizeof operator.

#include <iostream>
using namespace std;

int main()
{
    double pi;
    bool flag;
    char grade;

    cout << "Bytes taken up by pi is " << sizeof(pi) << endl;
    cout << "Bytes taken up by flag is " << sizeof(flag) << endl;
    cout << "Bytes taken up by grade is " << sizeof(grade) << endl;
    return 0;
}

Output:

Bytes taken up by pi is 8
Bytes taken up by flag is 1
Bytes taken up by grade is 1

Example 3:

This example demonstrates using sizeof to find the size of expressions.

#include <stdio.h>

int main() {
    int result;

    // Expression with multiple operators
    result = 10 * 5 + 8 / 2;

    printf("Result = %d\n", result);

    return 0;
}

Output:

Bytes taken up by (m + n) is 4
Bytes taken up by (m + x) is 8
Bytes taken up by (n + x) is 8

Output:

Bytes taken up by (m + n) is 4
Bytes taken up by (m + x) is 8
Bytes taken up by (n + x) is 8

Example 4:

This example uses sizeof to calculate the size of an array.

#include <iostream>
using namespace std;

int main()
{
    double values[] = {2.3, 4.6, 5.1, 8.9, 10.0};
    int length = sizeof(values) / sizeof(values[0]);
    cout << "Length of the array is " << length << endl;
    return 0;
}

Output:

Length of the array is 5

Example 5:

This example shows how to use sizeof to find the size of a class.

#include <iostream>
using namespace std;

class SampleClass
{
    char id;
    int count;
};

int main()
{
    SampleClass obj;
    cout << "Size of SampleClass object is: " << sizeof(obj) << " bytes" << endl;
    return 0;
}

Output:

Size of SampleClass object is: 8 bytes

Example 6:

This example demonstrates the size of different pointers using the sizeof operator.

#include <iostream>
using namespace std;

int main()
{
    int *ptrInt = new int(5);
    float *ptrFloat = new float(7.2);
    char *ptrChar = new char('A');

    cout << "Size of pointer ptrInt is " << sizeof(ptrInt) << endl;
    cout << "Size of *ptrInt is " << sizeof(*ptrInt) << endl;
    cout << "Size of pointer ptrFloat is " << sizeof(ptrFloat) << endl;
    cout << "Size of *ptrFloat is " << sizeof(*ptrFloat) << endl;
    cout << "Size of pointer ptrChar is " << sizeof(ptrChar) << endl;
    cout << "Size of *ptrChar is " << sizeof(*ptrChar) << endl;

    return 0;
}

Output:

Size of pointer ptrInt is 8
Size of *ptrInt is 4
Size of pointer ptrFloat is 8
Size of *ptrFloat is 4
Size of pointer ptrChar is 8
Size of *ptrChar is 1

Example 7:

This example demonstrates nesting of the sizeof operator.

#include <iostream>
using namespace std;

int main()
{
    int num = 3;
    double rate = 5.5;

    cout << "Nesting sizeof operator: sizeof(num * sizeof(rate)) is "
         << sizeof(num * sizeof(rate)) << endl;
    return 0;
}

Output:

Nesting sizeof operator: sizeof(num * sizeof(rate)) is 8

Example 8:

This example shows how to determine the size of a structure using sizeof.

#include <iostream>
using namespace std;

struct Record
{
    int id;
    float score;
    char name[50];
} record;

int main()
{
    cout << "Size of structure Record is " << sizeof(record) << endl;
    return 0;
}

Output:

Size of structure Record is 56

End of lesson.

Back to C++

C++ Operators

Operators in C++

Types of Operators in C

C++ sizeof Operator

The `sizeof` Operator in C++

C++ Operators

Operators in C++

Types of Operators in C

C++ sizeof Operator

The sizeof Operator in C++

The `sizeof` Operator in C++