Operators in C/C++

By: Er. Aman Kumar

Operators

• Operators are the special symbols that work on operand. Like in a + b, a and b are operands and + is special symbol (operator) which is working or operating on them.

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Types of Operators

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Assignment Operator

• Used to assign value to variable. = is assignment operator.

• NOTE: Value at right side is assigned to left side variable.

int a = 10;

int b = 55;

b = a;

Value of b will become 10 and value of a will remain as such.

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Lvalues and Rvalues

• lvalue : An expression that is an lvalue may appear as either the left-hand or right-hand side of an assignment.

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• rvalue : An expression that is an rvalue may appear on the right- but not left-hand side of an assignment.

• Variables are lvalues and so may appear on the left-hand side of an assignment. Numeric literals are rvalues and so may not be assigned and can not appear on the left-hand side.

• Following is a valid statement:

int g = 20;

• But following is not a valid statement and would generate compile-time error:

• 10 = 20;

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Arithmetic operators

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Priority of operators

• If 2 operators with same priority come?, then we will follow left to right rule. Means from left, which operator comes first, will be executed.

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Int i = 2 * 3 / 4 + 4 / 4 + 8 - 2 + 5 / 8 • i = 2 * 3 / 4 + 4 / 4 + 8 - 2 + 5 / 8

• i = 6 / 4 + 4 / 4 + 8 - 2 + 5 / 8 operation: *

• i = 1 + 4 / 4 + 8 - 2 + 5 / 8 operation: /

• i = 1 + 1+ 8 - 2 + 5 / 8 operation: /

• i = 1 + 1 + 8 - 2 + 0 operation: /

• i = 2 + 8 - 2 + 0 operation: +

• i = 10 - 2 + 0 operation: +

• i = 8 + 0 operation: -

• i = 8 operation: + way2ITech

Int i = 3 / 2 * 4 + 3 / 8 + 3

• i = 3 / 2 * 4 + 3 / 8 + 3

• i = 1 * 4 + 3 / 8 + 3 operation: /

• i = 4 + 3 / 8 + 3 operation: *

• i = 4 + 0 + 3 operation: /

• i = 4 + 3 operation: +

• i = 7 operation: +

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Arithmetical Calculations on Characters

• Arithmetic Calculations on characters can be done using ASCII codes

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Cyclic order in Integers

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WAP to enter small case character and Output upper case character

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Compound Arithmetic Assignment

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Unary Operators

• These are called as Unary operators as there is one operator and one operand only. It is two types:

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Rule to solve

• 1. Solve Pre

• 2. Solve Equation (ignore all pre and post and solve as normal equation)

• 3. Solve Post

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Comparison Operators

• They are used to compare value of 2 variables

• These operators deal in true or false. They return 0 if false and 1 (non zero number) for true.

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• NOTE:

There is difference in x = y and x == y.

x=y assigns value of variable y to variable x.

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Logical Operators

• They are used to combine two or multiple conditions.

• 1. And &&

• 2. OR ||

• 3. NOT !

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&& and || are useful in the following programming situations:

I. When it is to be tested whether a value falls within a particular range or not.

II. When after testing several conditions the outcome is only one of the two answers (This problem is often called yes/no problem or combine multiple conditions).

• These also work in Boolean Values (True/False). way2ITech

• Following table shows all the logical operators. Assume variable A holds 1 and variable B holds 0, then:

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Bitwise Operator

• This work in bits but takes input and gives Output in decimal form only.

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The truth tables for &, |, and ^ are as follows:

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Arithmetic shift • The two basic types are the

• arithmetic left shift (<<)

• arithmetic right shift (>>)

• For binary numbers it is a bitwise operation that shifts all of the bits of its operand; every bit in the operand is simply moved a given number of bit positions, and the vacant bit-positions are filled in.

• 23<<1 means shift bits of 23 by 1. Sly, 23>>1 means shift bits of 23 by 1.

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Bitwise Complement

• Here we add 1 and then change the sign

• ~N = - (N + 1)

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sizeof() operator

• This is used to get size in bytes for datatype, variable, structures, and union. It returns the size in bytes.

• sizeof(int) -> 2 (in blue screen TC)

• sizeof(char) -> 1

• sizeof(float) -> 4

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Ternary Operator or Conditional Operator ? :

Syntax

(condition) ? expression 1 : expression 2

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