Return Type Resolver

The return type resolver is a feature introduced in C++14 that allows the compiler to automatically deduce the return type of a function based on its implementation. It is commonly known as “automatic return type deduction” or “auto return type.”

The return type resolver is useful when the return type of a function depends on the types used in its implementation, such as the result of an expression or a template deduction. It eliminates the need for explicitly specifying the return type, making the code more concise and easier to maintain.

Here’s an example that demonstrates the use of the return type resolver:

#include <iostream>

// Function template with auto return type
template<typename T, typename U>
auto add(T a, U b) {
    return a + b;
}

// Function with auto return type
auto divide(int a, int b) {
    if (b != 0)
        return static_cast<double>(a) / b;
    else
        return 0.0;
}

int main() {
    // Calling the add function
    auto result = add(5, 3.14);
    std::cout << "Result of addition: " << result << std::endl;

    // Calling the divide function
    auto quotient = divide(10, 3);
    std::cout << "Result of division: " << quotient << std::endl;

    return 0;
}

In the above example, we have two functions: add and divide. The add function is a function template that takes two parameters of different types and returns their sum. The return type is deduced automatically by using auto as the return type specifier.

The divide function takes two int parameters and returns the quotient as a double. Here also, the return type is deduced using auto. If the second parameter b is not zero, the division operation is performed and the result is returned. Otherwise, it returns 0.0.

In the main function, we call both of these functions and store the return values in variables with auto type specifiers. We then print the results to the console.

The return type resolver allows the compiler to deduce the appropriate return type based on the implementation of the functions, eliminating the need for explicit return type declarations.