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The All-in-One Guide to C++20

Solution: Manage the Implicit Conversion

Explore how to manage implicit conversions in C++20 templates by leveraging compile-time predicates like std::is_same. Understand how this approach enforces type safety by restricting conversions, ensuring templates only accept intended types such as bool. This lesson helps you write clearer, more reliable template code through improved type control.

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Solution

C++
#include <iostream>
#include <type_traits>
#include <typeinfo>
struct MyBool {
    template <typename T>
    explicit(!std::is_same<T, bool>::value) MyBool(T t) {
        std::cout << typeid(t).name() << '\n';
    }
};
void needBool(MyBool b){}
int main() {
    MyBool myBool1(true);
    MyBool myBool2 = false;
    needBool(myBool1);
    needBool(true);
    // needBool(5);
    // needBool("true");
}

The explicit (!std::is_same<T, bool>::value) expression guarantees that MyBool can only be ...