A is a constructor that accepts no arguments. Typically, this is a constructor that has been defined with no parameters. Here is an example of a class that has a default constructor: #include <iostream> class Foo { public: Foo() // default constructor { std::cout << “Foo default constructed\n”; } }; …
In a previous lesson (), we mentioned that the member variables of a class are typically made private. Programmers who are learning about classes for the first time often have a hard time understanding why you’d want to do this. After all, making your variables private means they can’t be …
In the previous chapter, we covered structs (), and discussed how they are great for bundling multiple member variables into a single object that can be initialized and passed around as a unit. In other words, structs provide a convenient package for storing and moving related data values. Consider the …
The cleanup problem Let’s say that you are writing a program that needs to send some data over a network. However, establishing a connection to the server is expensive, so you want to collect a bunch of data and then send it all at once. Such a class might be …
A function and its caller communicate with each other via two mechanisms: parameters and return values. When a function is called, the caller provides arguments, which the function receives via its parameters. These arguments can be passed by value, reference, or address. Typically, we’ll pass arguments by value or by …
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 printRef(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 …
