C++ BasicsTutorial 6Operators

What are going to see today?

• Assignment operator(=)• Arithmetic operators(+,-,*,/,%)• Compound assignment(+=,-=,*=……..)• Increment and decrement(++, --)• Relational and equality(==, !=, >, <. >=, <=)• Logical(!, &&, ||)• Conditional(?:)• Comma operator(,)• Bitwise operator(&, |, ^, ~, <<, >>)• sizeof()• Precedence

Assignment operator(=)

• Assign a value to variable• Example: x=23;

• Right to left rule. Assigns always the right part to left.• C++ allows to use ‘=‘ as rvalue too• Example x=23+(y=53); is same as • y=53; x = 23+y;

• Multiple assignment operator is also valid• a=b=c= 23 assigns 23 to all a, b and c

lvalue

rvalue

Arithmatic operators (+, -, /, *, %)

• + is addition, - is subtraction, * multiplication, / is division and % is modulo.

• When % is used between two numbers it will give the remainder of the division between two numbers.• Example: 15%4 = 3

Compound Assignment(+=, -=, *=, /=, %=, >>=, <<=, &=, ^=, |=)

• Changing the value of a variable, using the current value stored in the same variable, compound assignment become useful• Example: a+=5 is same as a = a+5 (add 5 more to whatever

is in a and replace the old value of a to a+5). Similar to a-=5; or a/=5,

• a*=b%2 is same as a = a*(b%2);

Increment and Decrement (++, --)

• ++: Increment the value in variable by one unit• Same as +=1; • Example: a++, a+=1; both increase the value of a by one.

• --: Decrement the value stored in variable by one unit• Same as -=1;• Example a--, a-=1; both decrease the value of a by one.

• Can be used and prefix or suffix• Example a++ or ++a• In case result of this operation and evaluated and stored, writing a++ or +

+a makes a big difference.• Example: a=5; b=a++; gives us a=6 and b=5 • But a = 5; b=++a; gives a=6 and b=6

Relational and equality operators (==, !=, >, <, >=, <=)

• == Equal to? (not same as ‘=‘)• != Not equal to?• > greater than?• < smaller than?• >= greater than or equal to?• <= smaller than or equal to?• Example: (23==53) is false (23>=23) is true• Or using variable:• (a>b) returns true if a is bigger than b• (a!=b) returns true if a is not equal to b

Logical operators(&&, ||, ! )

• && and || are used to obtain a relational result between two expressions.• Example: If we have two expression a and b, then we can use as (a && b) or

(a||b). • Using && will give result as true only of both expression are true and false

otherwise whereas || will give false only if both expression are false and true otherwise.

• && corresponds to boolean logic AND• || corresponds to boolean logic OR

• ! Corresponds to boolean logic NOT• Is located on the left of operand.• Inverses the value of operand• Example (!(23==23)) is returned as false.

Conditional operator( ? : )

• It evaluates an expression and returns a result.• Condition ? (Return If True) : (Return If False)• Example: (7>5)?10:20 Will return 20 because 7 is greater

than 5.• (7<5)?10:20 will return 20 because 7 < 5 is a false

statement.• (!(5==5))?1:2 will return 2 because 5 is equal to 5 but ! will

change that true to false statement hence 2 is returned.

Comma Operator (,)

• Used when two or more expressions is included where only one is expected• Example: x = (y=27, y+23); will first assign 27 to y and

store 50 (y+23=27+23=50) to x.

Bitwise operators(&, |, ^, ~, <<, >>)

• Used only when working with bits of data on low level.• Currently we are only working on bytes of data.• & is bitwise AND• | is bitwise OR• ^ is bitwise XOR• ~ is bitwise NOT• << shift left (SHL)• >> shift right (SHR)

Explicit type casting operators

• Type casting: converting a data type from one to the other.• Example: int a;

float b = 6.67;a = (int)b (or, a = int(b);) will have a = 6.

sizeof()

• Return size in bytes for a data type or variable itself.• Example SizeOfChar = sizeof(char) will store 1 to variable

SizeOfChar because the size of char data type is 1 bytes (we talked about it in previous videos)

Other??

• There are other operators that we will go on later when we get to pointers and specific object oriented programming.

Precedence

• Order in which the operators are performed according to the priority. Priority order is defined for each operators.

• For basic leve:• Level 1 is :: (called scope)• Level 2: () or []• Level 3: ++, --• Level 4: Type casting (type)• Level 5: * / % (Goes from left to right)• Level 6: +, - (Left to right)• Level 7: <, >, <=, >= relational (left to right)• Level 8: ==, !=• Level 9: bitwise operators• Level 10: && Logical AND (left to right)• Level 11: || Logical OR (left to right)• Level 12: ?: conditional (right to left)• Level 13: =, /= … Assignment operators (Right to left)• Level 14: comma(,) left to right

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