Math Operation	C++ Operator
Add	+
Subtract	-
Multiply	*
Divide	/
Mod	%

For integers A and B,
A % B returns the remainder when A is divided by B.
A/B returns the quotient when A is divided by B.

Examples: 20/3 = 6

20%3 = 2

20%20 = 0

Note that if one of the operands is floating point the value of the expression is floating point.

20.0/3 = 6.666667

20/3.0 = 6.666667

Order of Precedence of Operations:

1. All operators within parentheses
2. If there are nested parentheses innermost are performed first
3. *, /, % are performed from left to right
4. +, - are performed from left to right

Example:

5/4*9 + 10%7 = 1*9 + 3 = 12.

Problem: Compute average of integer variable objects A, B, C, D and assign to integer variable Average.

Average = (A + B + C + D)/4;

Suppose that A, B, C, D have values 3, 3, 3, 2, respectively, Then, Average is assigned the value (3 + 3 + 3 + 2)/4 = 11/4 = 2.

What if we wish to round to the nearest integer. Answer:

Average = (A + B + C + D)/4.0 + .5;

Computer first computes:

(A + B + C + D)/4.0 + .5 = 2.75 + .5 = 3.25

Then 3.25 is assigned to Average. But because Average is an integer object variable, it is assigned the value 3.

Increment and Decrement Operators

y = ++x; same as x = x + 1; y = x; //PREINCREMENT
y = --x; same as x = x - 1; y = x; //PREINCREMENT
y = x++; same as y = x; x = x + 1; //POSTINCREMENT
y = x--; same as y = x; x = x - 1; //POSTINCREMENT

Avoid ambiguous expressions such as

3*X+++Y

Use parentheses, i.e.

(3*X++)+ Y

Assignment Operators A = B; assigns value of B to A

A += B; same as A = A+B;
A -= B; same as A = A-B;
A *= B; same as A = A*B;
A /= B; same as A = A/B;
A %= B; same as A = A%B;

Boolean Relational Operators

Boolean Operation	C++ Operator
equal	==
not equal	!=
less than	<
less than or equal	<=
greater than	>
greater than or equal	>=

In C++ false has value 0 and true has value 1.

Example:

7 == 7 has value 1 (true)

BE CAREFUL:

7 = 7 has value 7 (since = is the assignment operator!)

Other examples:

'A' < 'Y' has the value 1 (true)

'a' < 'B' has the value 0 (false)

7 != 6 has the value 1 (true)

7 >= 13 has the value 0 (false)

Logical Operators

Logical Operation	C++ Operator
NOT	!
OR	||
AND	&&

Truth Tables

NOT (!)	T	F
	F	T

OR (||)	T	F
T	T	T
F	T	F

AND (&&)	T	F
T	T	F
F	F	F

Examples:

(5<7)&&(8==6) has value 0 (false)

(5<7)&&(8!=6) has value 1 (true)

(5<7)||(8==6) has value 1 (true)