If Statements in

About If Statements

Conditionals in C++ are similar to conditionals in other languages. The underlying type of any conditional operation is the bool type, which can have the value of true or false. Conditionals are often used as flow control mechanisms to check for various conditions.

An if statement can be used, which executes its code if the underlying condition is true like this:

std::string value{"val"};

if (value == "val") {
    return "was val";
}

In scenarios involving more than one case many if statements can be chained together using the else if and else statements.

int number{33};

if (number > 0) {
   return "positive";
} else if (number < 0) {
    return "negative";
} else {
   return "zero";
}

Since C++17 if-statements can also include a short initialization statement that can be used to initialize one or more variables for the if statement. For example:

int num{7};
if (int v{2 * num}; v > 10) {
    return v;
} else {
    return num;
}
// => 14

Note: any variables created in the initialization cannot be accesed after the end of the if statement.