else

The first substatement of an if statement may be followed by the keyword else. The substatement after the else keyword will be executed when the condition is falsey (that is, when the first substatement is not executed).

int x;
std::cin >> x;
if (x % 2 == 0) {
    std::cout << "The number is even\n";
} else {
    std::cout << "The number is odd\n";
}