Conditionals allow you to execute different blocks of code based on whether a condition is true or false.

Use these for decision-making in your algorithms (e.g., checking if a number is even, or if a user is authorized).

• Check: $O(1)$

cpp Standard
int age = 18;
if (age >= 18) {
    std::cout << "Eligible to vote!" << std::endl;
} else {
    std::cout << "Not eligible." << std::endl;
}

• Using = instead of == in the condition.
• Forgetting {} for multi-line blocks (though single lines don't strictly require them, it's best practice).
• Redundant conditions: if (x == true) is same as if (x).