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 provides the following types of operators:

1.  Arithmetic Operators
2. Relational Operators
3. Logical Operators
4. Increment & decrement operator
5. Assignment Operators
6. Conditional operator.
7. The Comma (,) operator.
8. Sizeof operator.
9. Scope resolution operator (::)
10. ‘new’ operator

1)    Arithmetic Operators: Arithmetical operators +, -, *, /, and % are used to performs an arithmetic (numeric) operation. You can use the operators +, -, *, and / with both integral and floating-point data types. Modulus or remainder % operator is used only with the integral data type.

 

2)  Relational operators: The relational operators are used to test the relation between two values. All relational operators are binary operators and therefore require two operands. A relational expression returns zero when the relation is false and a non-zero when it is true.

Relational Operators	Meaning
<	Less than
<=	Less than or equal to
==	Equal to
>	Greater than
>=	Greater than or equal to
! =	Not equal to

 

3)      Logical operators: The logical operators are used to combine one or more relational expression. The logical operators are

Operators	Meaning
||	OR
&&	AND
!	NOT

        

        AND(&&): evaluates true when both the relations expressions are true.

        OR(||) : Evaluates true when any one of the relation expression becomes true.

        NOT(!) : this operator reverse the truth value of the expression.

4)   Increment & decrement operator: C++ provides two special operators '++' and '--' for incrementing and decrementing the value of a variable by 1.. Increment and decrement operators each have two forms, pre and post.

 

The syntax of the increment operator is:          Pre-increment: ++variable

 

Post-increment: variable++

 

The syntax of the decrement operator is:         Pre-decrement: --variable

 

Post-decrement: variable --

 

In Prefix form first variable is first incremented /decremented, then evaluated, In Postfix form first variable is first evaluated, then incremented/decremented

 

5)    Assignment operator: The assignment operator ' = ' is used for assigning a variable to a value. This operator takes the expression on its right-hand-side and places it into the variable on its left-hand-side. 

For example:

m = 5;

 The operator takes the expression on the right, 5, and stores it in the variable on the left, m.

x = y = z = 32;

This code stores the value 32 in each of the three variables x, y, and z.

In addition to standard assignment operator shown above, C++ also supports compound assignment operators.

6)   Conditional operator: The conditional operator?: is called ternary operator as it requires three operands. The format of the conditional operator is:

Conditional_ expression ? expression1 : expression2;

If the value of conditional expression is true then the expression1 is evaluated, otherwise expression2 is evaluated.

int a = 5, b = 6;

big = (a > b) ? a : b;

The condition evaluates to false, therefore biggest the value from b and it becomes 6.

7)  The comma operator: The comma operator gives left to right evaluation of expressions. When the set of expressions has to be evaluated for a value, only the rightmost expression is considered.

 

int a = 1, b = 2, c = 3, i; // comma acts as separator, not as an operator i = (a, b); // stores b into i

Would first assign the value of a to i, and then assign value of b to variable i. So, at the end, variable i would contain the value 2.

8) The sizeof operator : As we know that different types of Variables, constant, etc. require different amounts of memory to store them The sizeof() operator can be used to find how many bytes are required for an object to store in memory.

 

For example   sizeof (char) returns 1 , sizeof (float) returns 4 .

9) Scope Resolution operator (:: ) It is special operator in c++ it used in managing variables

and members at outside of active bounders . It enables

-          accessing global variable

-          setting and accessing static-member

-          implementing the member-function

1. It used to access global variable when local variable and global variables are

same.

:: x

2. It used to set and access static-member at outside of class with the class name and membername.

int  Karim :: x

3. It used to implement the member-function of a class at outside of a class

void Karim::show(){ }

10) ‘new’ Operator: The memory allocation operator it allocates memory dynamically for

specific class-object .

void main

{

Maxi *k=new Maxi();

k->show();

}

The order of Precedence of Arithmetic Operators:

The order in which the Arithmetic operators (+,-,*,/,%) are used in a. given expression is called the order of precedence. The following table shows the order of precedence.

 

First                ( )               

Second           *, /, %        

            Third               +, -