Consider the following program, which doesn’t work correctly: main.cpp: #include <iostream> template <typename T> T addOne(T x); // function template forward declaration int main() { std::cout << addOne(1) << ‘\n’; std::cout << addOne(2.3) << ‘\n’; return 0; } add.cpp: template <typename T> T addOne(T x) // function template definition { …
In lesson , we covered constexpr functions, which are functions that may be evaluated at either compile-time or runtime. For example: #include <iostream> constexpr int greater(int x, int y) { return (x > y ? x : y); } int main() { std::cout << greater(5, 6) << ‘\n’; // greater(5, …
The following program is designed to print the name of the language standard your compiler is currently using. You can copy/paste, compile, and run this program to validate that your compiler is using the language standard you expect. PrintStandard.cpp: // This program prints the C++ language standard your compiler is …
In the prior lesson (), we showed this example, where we used a function to convert an enumeration into an equivalent string: #include <iostream> #include <string_view> enum Color { black, red, blue, }; constexpr std::string_view getColorName(Color color) { switch (color) { case black: return “black”; case red: return “red”; case …
In the prior lesson (), we showed an example like this: #include <iostream> enum Color { black, // 0 red, // 1 blue, // 2 }; int main() { Color shirt{ blue }; std::cout << “Your shirt is ” << shirt << ‘\n’; return 0; } This prints: Your shirt …
In lesson , we discussed cases where a function encounters an error that it cannot reasonably handle itself. For example, consider a function that calculates and returns a value: int doIntDivision(int x, int y) { return x / y; } If the caller passes in a value that is semantically …
What is C++23? In February of 2023, the ISO (International Organization for Standardization) approved a new version of C++, called C++23. New improvements in C++23 For your interest, here’s a list of the major changes that C++23 adds. Note that this list is not comprehensive, but rather intended to highlight …
When we need to pass a std::vector to a function, we pass it by (const) reference so that we do not make an expensive copy of the array data. Therefore, you will probably be surprised to find that it is okay to return a std::vector by value. Say whaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaat? Copy …
Nice work. Function templates may seem pretty complex, but they are a very powerful way to make your code work with objects of different types. We’ll see a lot more template stuff in future chapters, so hold on to your hat. Chapter Review allows us to create multiple functions with …
What happens if we want to use a random number generator in multiple functions or files? One way is to create (and seed) our PRNG in our main() function, and then pass it everywhere we need it. But that’s a lot of passing for something we may only use sporadically, …
