Motivation

Type traits provide a compile-time mechanism to query and manipulate properties of types using templates.

Example

Using type traits, we can write a template that behaves differently depending on whether a type is an integral type or not. For instance:

  
#include <type_traits>
#include <iostream>

template <typename>
void print_type_info(T value) {
    if constexpr (std::is_integral<t>::value) {
        std::cout << "Integral type: " << value << "\n";
    } else {
        std::cout << "Non-integral type: " << value << "\n";
    }
}

int main() {
    print_type_info(42);       // Integral type
    print_type_info(3.14);     // Non-integral type
}

In this example, std::is_integral<T> is a type trait that tells us at compile time whether T is an integral type, enabling different behavior without runtime overhead.