Operators

Operators let you combine, compare, and manipulate values. C++ groups them into arithmetic, relational, logical, and assignment categories, each with its own precedence rules.

Arithmetic and Assignment Operators

The standard arithmetic operators (+ - * / %) behave as expected, with one caveat: dividing two integers performs integer division, discarding any remainder. Compound assignment operators like += update a variable in place.

int a = 7, b = 2;
std::cout << a / b << std::endl;       // 3 (integer division)
std::cout << a % b << std::endl;       // 1 (remainder)
std::cout << (double)a / b << std::endl; // 3.5 (cast to force decimal)

int score = 10;
score += 5;  // same as score = score + 5
score *= 2;  // same as score = score * 2

Relational and Logical Operators

Relational operators compare two values and produce a bool. Logical operators combine boolean expressions, which is how conditions with multiple requirements are built.

• == != > < >= <= — comparison, all return bool.
• && — logical AND, true only if both sides are true.
• || — logical OR, true if at least one side is true.
• ! — logical NOT, flips a boolean value.

Common Mistakes

• Using a single = (assignment) when you meant == (comparison) inside a condition.
• Forgetting that integer division truncates — 7 / 2 is 3, not 3.5.
• Mixing up && and || when combining multiple conditions.
• Not using parentheses to clarify operator precedence in a complex expression.