Unlike a reference to non-const (which can only bind to modifiable lvalues), a reference to const can bind to modifiable lvalues, non-modifiable lvalues, and rvalues. Therefore, if we make a reference parameter const, then it will be able to bind to any type of argument: #include <iostream> void printValue(const int& …
Structs with program-defined members In C++, structs (and classes) can have members that are other program-defined types. There are two ways to do this. First, we can define one program-defined type (in the global scope) and then use it as a member of another program-defined type: #include <iostream> struct Employee …
Normally, the conditional of an if-statement is evaluated at runtime. However, consider the case where the conditional is a constant expression, such as in the following example: #include <iostream> int main() { constexpr double gravity{ 9.8 }; // reminder: low-precision floating point literals of the same type can be tested …
In the previous lesson (), we covered numeric conversions, which cover a wide range of different type conversions between fundamental types. Narrowing conversions In C++, a is a potentially unsafe numeric conversion where the destination type may not be able to hold all the values of the source type. The …
In the previous lessons, we discussed how to create function templates that use type template parameters. A type template parameter serves as a placeholder for an actual type that is passed in as a template argument. While type template parameters are by far the most common type of template parameter …
A tip o’ the hat to reader Avtem for conceiving of and collaborating on this project. Project time Let’s implement the classic game 15 Puzzle! In 15 Puzzle, you begin with a randomized 4×4 grid of tiles. 15 of the tiles have numbers 1 through 15. One tile is missing. …
In prior lesson , we covered how the const keyword could be used to make a variable a constant variable whose value cannot be changed. In this lesson, we’ll take a look at another property of constants: whether they are runtime constants or compile-time constants. The as-if rule In C++, …
Author’s note This lesson is optional. Future lessons reference hexadecimal numbers, so you should at least have a passing familiarity with the concept before proceeding. In everyday life, we count using numbers, where each numerical digit can be 0, 1, 2, 3, 4, 5, 6, 7, 8, or 9. Decimal …
In prior lessons, we introduced two string types: std::string () and std::string_view (). Because std::string_view is our first encounter with a view type, we’re going to spend some additional time discussing it further. We will focus on how to use std::string_view safely, and provide some examples illustrating how it can …
Class template argument deduction (CTAD) C++17 Starting in C++17, when instantiating an object from a class template, the compiler can deduce the template types from the types of the object’s initializer (this is called or for short). For example: #include <utility> // for std::pair int main() { std::pair<int, int> p1{ …
