C++ Operators and Precedence: The Complete Master Reference Guide

An Operator is a special symbol that tells the compiler to perform specific mathematical, relational, or logical manipulations on operands. C++ features a rich variety of operators with strict precedence and associativity rules.

Key Operator Categories

Arithmetic Operators: +, -, *, /, % (modulus).
Relational / Comparison Operators: ==, !=, >, <, >=, <=, and C++20 Three-way comparison <=> (spaceship operator).
Logical Operators: && (AND), || (OR), ! (NOT).
Bitwise Operators: &, |, ^ (XOR), ~ (NOT), << (left shift), >> (right shift).
Assignment Operators: =, +=, -=, *=, /=, %=, &=, |=.
Ternary Conditional Operator: condition ? expr1 : expr2.

Operator Precedence Summary Table (Highest to Lowest)

Precedence Level	Operators	Associativity
1 (Highest)	Scope resolution `::`	Left to Right
2	Member access `.`, `->`, Subscript `[]`, Function call `()`, Postfix `++`, `--`	Left to Right
3	Prefix `++`, `--`, Unary `+`, `-`, Logical NOT `!`, Bitwise NOT `~`, Dereference `*`, Address-of `&`, `sizeof`	Right to Left
4	Multiplication `*`, Division `/`, Modulo `%`	Left to Right
5	Addition `+`, Subtraction `-`	Left to Right
6	Bitwise Shift `<<`, `>>`	Left to Right
7	Relational `<`, `<=`, `>`, `>=`	Left to Right
8	Equality `==`, `!=`	Left to Right
9	Logical AND `&&`	Left to Right
10	Logical OR `\|\|`	Left to Right
11	Ternary Conditional `? :`	Right to Left
12 (Lowest)	Assignment `=`, `+=`, `-=`, Comma `,`	Right to Left

Frequently Asked Questions (FAQ) - Student & Interview Review

Q1. What is Short-Circuit Evaluation in C++ logical operators?

In logical AND (&&), if the left condition evaluates to false, the right condition is never executed because the whole expression cannot be true. In logical OR (||), if the left condition is true, the right condition is skipped. This is critical for preventing null pointer dereferences (e.g., if (ptr != nullptr && ptr->val > 0)).

Q2. What is the difference between prefix (++x) and postfix (x++) increment?

Prefix (++x) increments the value immediately and returns the newly incremented value. Postfix (x++) makes a temporary copy of the current value, increments the original variable, and returns the old copy. In modern C++ loops and iterators, prefix (++it) is preferred for performance.