operators lect2

8/3/2019 Operators Lect2

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OPERATORS AND EXPRESSIONS


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Definition

An operator is a symbol (+,-,*,/) that directs the computer to performcertain mathematical or logical manipulations and is usually used tomanipulate data and variables

Ex: a+b

Where + is operator and a, b are the operands.


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Operators in C1. Arithmetic operators

2. Relational operators

3. Logical operators4. Assignment operators

5. Increment and decrement operators

6. Conditional operators

7. Bitwise operators8. Special operators


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Arithmetic operators

Operator example Meaning

+ a + b Addition unary

- a b Subtraction- unary

* a * b Multiplication

/ a / b Division

% a % b Modulo division- remainder


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Example main()

{

int a=12,b=3,c;

c=a%b;

printf(%d,c);

}

Arithmetic operators can be classified as

i) unary arithmetic-Requires only one operand. Eg: +x.

ii) Binary arithmetic-Requires two operands. Eg: a+b.

iii) Integer arithmetic-Requires two operands and integervalues. Eg: a+b. where a=6,b=4.

iv) Floating point arithmetic-Requires both operands and floattype for arithmetic operations.


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Relational Operators

Operator Meaning

< Is less than Is greater than

>= Is greater than or equal to== Equal to

!= Not equal to


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#include

#include

{Clrscr();

Printf(\n condition:return values\n);

Printf(\n 5!=5: %5d,5!=5);

Printf(\n 5==5 : %5d, 5==5);

}


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Logical Operators

Operator Meaning example

&& Logical AND (exp1)&&(exp2)

|| Logical OR (exp1)||(exp2)

! Logical NOT !(exp1)

Logical expression or a compound relationalexpression-

An expression that combines two or morerelational expressions

Ex: if (a==b && b==c)


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Truth Table

a bValue of the expression

a && b a || b

0 0 0 00 1 0 1

1 0 0 1

1 1 1 1

a < b && b < c

1 2

3


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#include

#include

{

int a,b,c;Clrscr();

Printf(\n enter values\n);

Scanf(%d%d%d,&a,&b,&c);

If((a


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Assignment operatorsSyntax:

v=exp or value;

v op = exp;Where v = variable,

op = shorthand assignment operator

exp = expression

Ex: x=x+3

x+=3


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Shorthand Assignment operatorsSimple assignment

operatorShorthand operator

a = a+1 a + =1

a = a-1 a - =1

a = a* (m+n) a * = m+n

a = a / (m+n) a / = m+n

a = a %b a %=b


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Increment & Decrement OperatorsC supports 2 useful operators namely

1. Increment ++

2. Decrement operators

The ++ operator adds a value 1 to the operand

The operator subtracts 1 from the operand

++a or a++

--a or a--


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Rules for ++ & -- operators

1. These require variables as their operands

2. When postfix either ++ or is used with the

variable in a given expression, the expression isevaluated first and then it is incremented ordecremented by one

3. When prefix either ++ or is used with the

variable in a given expression, it is incrementedor decremented by one first and then theexpression is evaluated with the new value


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Examples for ++ & -- operatorsLet the value of a =5 and b=++a thena = b =6Let the value of a = 5 and b=a++ thena =5 but b=6i.e.:1. a prefix operator first adds 1 to the operand and

then the result is assigned to the variable on theleft

2. a postfix operator first assigns the value to thevariable on left and then increments the operand.


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Conditional operatorsSyntax:

exp1 ? exp2 : exp3

Where exp1,exp2 and exp3 are expressions

Working of the ? Operator:Exp1 is evaluated first, if it is nonzero(1/true) then the expression2 is

evaluated and this becomes the value of the expression,

If exp1 is false(0/zero) exp3 is evaluated and its value becomes the valueof the expression

Ex: m=2;

n=3

r=(m>n) ? m : n;


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Bitwise operators

These operators allow manipulation of data at the bit level

Operator Meaning

& Bitwise AND

| Bitwise OR

^ Bitwise exclusive OR

> Shift right


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Special operators1. Comma operator ( ,)

2. sizeof operator sizeof( )

3. Pointer operators ( & and *)4. Member selection operators ( . and ->)


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ExampleEvaluate the expression when a=4

b=a- ++a

=a 5=5-5

=0

operators lect2

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