Control Structures & Operator
 
Precedence of Operators
 
Writing complex expressions with more than a one operands, we may have a number of misgivings about which operand is evaluated foremost and which afterward.
 
For example, in this appearance:
 
i = 4 + 3% 2
 
we may hesitation if it actually means:
 
i = 4+ (3% 2)
i = (4 + 3) % 2
 
The right answer is the first of the two expressions, with i answer of 5.
 
There is an established order with the precedence of each operator, and not only the arithmetic ones but for all the operators which can appear in C++.
 
From greatest to lowest priority, the priority order is as follows:
 
Level Operator Description Grouping
1 :: scope Left-to-right
2 () [] . -> ++ -- dynamic_cast static_cast reinterpret_cast const_cast typeid postfix Left-to-right
3

++ -- ~ ! sizeof new delete

*&

+-

unary (prefix)

indirection and reference (pointers)

unary sign operator

 Right-to-left
4 (type) type casting Right-to-left
5 .&->* pointer-to-member Left-to-right
6 */% multiplicative Left-to-right
7 +-

additive
Left-to-right
8 <<>> shift Left-to-right
9 <><= >= relational Left-to-right
10 == != equality Left-to-right
11 & bitwise AND Left-to-right
12 ^

bitwise XOR
Left-to-right
13 l bitwise OR Left-to-right
14 && logical AND Left-to-right
15 ll logical OR Left-to-right
16 ?: conditional Right-to-left
17

= *= /= %= += -= >>= <<= &= ^= !=
assignment Right-to-left
18 , comma Left-to-right
 
i = 4 + 3% 2;
 
might be written either as:
 
i = 4 + (3 % 2);
Or

i = (4 + 3) % 2;
 
depending on the operation that we want to perform.