OPERATORS IN C/C++

C/C++ programs are made with the chief intention of solving a certain task. These tasks can be from simple day to day calculations to complex algorithms. But in all these tasks one thing that is common is that we need to compute certain expressions. We need to take inputs from user, then calculate the desired result and output the result on the screen. All these actions are completed using special tokens called the Operators.

 

OPERATORS IN C/C++

 

The operators in C++ are classified into many categories. In this article we will learn about them in very short.

In a program, we perform various operations on data. Operators let us perform operations on your data.

C++’s rich set of operators comprise of I/O, arithmetic, relational, logical and certain other types of operators.

 

I/O Operators :

Input coming from the user’s terminal, referred to as standard input is tied to the predefined iostream cin and output directed to the user’s terminal, referred to as standard output, is tied to the predefined iostream cout.

Output operator (“<<”) : The output operator (“put to”) is used to direct a value to standard output. For instance,

cout<< “The sum of 6 & 2 is ”;

cout<< 6+2;

Output :        

            The sum of 6 & 2 is 8

Input Operator (“>>”) : The input operator (“get from”) is used to read a value from standard input.

            int n;

            cin>> n;

This takes input from the user till he hits enter.

Also, many of these operators can be used together to take many inputs or to give many outputs. (It’s called Cascading)

cout<< “Learn ” << “to ” << “code ”;

Output :

            Learn to code

 

Arithmetic Operators :

To do arithmetic, C++ uses operators. It provides operators for five basic arithmetic calculations : addition, subtraction, multiplication, division and modulus which are +, -, *, /, % respectively.

Each of these operators is a binary operator i.e. it requires two values (operands) to calculate a final answer. Apart from these binary operators, C++ provides two unary arithmetic operators : unary plus and unary minus.

The arithmetic operators in C++ have the same function as they have in mathematics. The modulus operator (%) produces the remainder of dividing the first operand by second. But both the operands must be integer types here. Rest all other operators can work with integer and floating-point values.

Let us see the workings briefly :

cout<< 8+6<< “ ”;

cout<< 8-6<< “ ”;

cout<< 8*6<< “ ”;

cout<< 8/6<< “ ”;

cout<< 8%6;

Output : 14 2 48 1 2

Note that 8/6 yields 1 and not 1.33. This is due to the fact that both operands 8 & 6 are integers and so the entire expression works as integers. We can understand it as 8 = 6 * (1) + 2; So, the integer division yields 1 and the modulus yields the remainder 2.

 

Increment/Decrement Operators :

 

The increment operator, ++, adds 1 to its operand and the operator – subtracts 1 from its operands. That is, a = a+1 is equal to a++ (or ++a) and a = a-1 is equal to a—(or --a).

The two forms are called postfix and prefix.

Postfix :  a++  or  a—

Prefix   :  ++a  or  --a

The postfix form of ++, -- operators follow the rule use-then change. For example,

int sum = 6;

int c = 2;

sum = sum + (c++);

cout<< “Sum = ” <<sum<<endl;

cout<< “ c = ” <<c;

Output :    Sum = 8

                    c = 3

 

The prefix form of ++,-- operators follow the rule change-then-use. For example,

int sum = 6;

int c = 2;

sum = sum + (++c);

cout<< “Sum = ” <<sum<<endl;

cout<< “ c = ” <<c;

Output :    Sum = 9

                    c = 3

Note :

Increment/Decrement operators have a higher precedence than the arithmetic operators.

Post fix form is at higher precedence than prefix form.

 

Relational Operators :

 

Relational operators determine the relation among different operands. C++ provides six relational operators for comparing numbers and characters. But they do not work on arrays.

Each of these operators is binary and returns a Boolean value (i.e. either true or false). If an expression is true, it returns true (or 1) and if the expression is false, it returns false (or 0).

The six relational operators are :

<     (less than)    

>     (greater than)

<=  (less than or equal to)

>=  (greater than or equal to)

==  (equal to)

!=   (not equal to)

 

Logical Operators :
 

C++ provides for 3 logical operators to combine existing expressions. These are || (logical OR), && (logical AND) and ! (logical NOT). Let us examine them :

The logical OR operator (||) : It evaluates true if any of the operands evaluate true, else false.

The logical AND operator(&&) : It combines two expressions together just like OR. The resulting expression has the value 1 (i.e. true) only if both of the original expressions (its operands) are true.

The logical NOT operator (!) : This operator, unlike the other two, works on a single expression (operand),i.e. it is a unary operator. It negates or reverses the truth value of an expression, i.e. if the expression is true, then ! (expression) is false and vice versa.

 

Conditional Operator :

 

C++ offers one conditional operator, which is also popularly called as ternary operator as it needs 3 operands to work.

General syntax :

expression 1 ? expression 2 : expression 3;

If expression 1 is true, then the value of the whole expression is the value of expression 2, otherwise, the value of the whole expression is the value of expression 3.

Example :

int marks = 58; char grade;

grade = marks>=50 ? ‘P’ : ‘F’ ;

cout<< “The grade is ”<<grade;

Output : The grade is P

 

int marks = 48; char grade;

grade = marks>=50 ? ‘P’ : ‘F’ ;

cout<< “The grade is ”<<grade;

Output : The grade is F

 

Note : The value holding variable (here grade) must be of the correct data type.

 

Some other Operators :

The Compile-Time Operator sizeof() : It is a unary compile-time operator that returns the length (in bytes) of the variable or any type-specifier which is put within the parenthesis.

It can be used 2 forms :

sizeof var;       // where var is a declared variable

sizeof (type);  // where type is any C++ data type

 

The Comma Operator : A comma operator is used to string together several expressions. The group of expressions separated by commas (,) is evaluated left-to-right in sequence and the result of the right-most expression becomes the value of the total comma-separated expression.

For example,

int a=3,b;

b = (a+1,a+3);

cout<<b;

Output : 6

Evaluating left to right, a+1 = 4; then a+3 = 6. As a+3 is the rightmost expression, it is stored in b.

 

 

 

 

 

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