C++ supports two variants of namespaces that are worth at least knowing about. We won’t build on these, so consider this lesson optional for now. Unnamed (anonymous) namespaces An (also called an ) is a namespace that is defined without a name, like so: #include <iostream> namespace // unnamed namespace …
Each block defines its own scope region. So what happens when we have a variable inside a nested block that has the same name as a variable in an outer block? When this happens, the nested variable “hides” the outer variable in areas where they are both in scope. This …
In some applications, certain symbolic constants may need to be used throughout your code (not just in one location). These can include physics or mathematical constants that don’t change (e.g. pi or Avogadro’s number), or application-specific “tuning” values (e.g. friction or gravity coefficients). Instead of redefining these constants in every …
In the prior lesson (), we discussed how internal linkage limits the use of an identifier to a single file. In this lesson, we’ll explore the concept of external linkage. An identifier with can be seen and used both from the file in which it is defined, and from other …
In lesson , we said, “An identifier’s linkage determines whether other declarations of that name refer to the same object or not”, and we discussed how local variables have no linkage. Global variable and functions identifiers can have either internal linkage or external linkage. We’ll cover the internal linkage case …
In the previous lesson (), we introduced this example: #include <algorithm> #include <array> #include <iostream> #include <string_view> int main() { std::array<std::string_view, 4> arr{ “apple”, “banana”, “walnut”, “lemon” }; auto found{ std::find_if(arr.begin(), arr.end(), [](std::string_view str) { return str.find(“nut”) != std::string_view::npos; }) }; if (found == arr.end()) { std::cout << “No nuts\n”; …
Consider this snippet of code that we introduced in lesson : #include <algorithm> #include <array> #include <iostream> #include <string_view> // Our function will return true if the element matches bool containsNut(std::string_view str) { // std::string_view::find returns std::string_view::npos if it doesn’t find // the substring. Otherwise it returns the index where …
New programmers typically spend a lot of time writing custom loops to perform relatively simple tasks, such as sorting or counting or searching arrays. These loops can be problematic, both in terms of how easy it is to make an error, and in terms of overall maintainability, as loops can …
Iterating through an array (or other structure) of data is quite a common thing to do in programming. And so far, we’ve covered many different ways to do so: with loops and an index (for-loops and while loops), with pointers and pointer arithmetic, and with range-based for-loops: #include <array> #include …
With many different versions of C++ available (C++98, C++03, C++11, C++14, C++17, C++20, C++23, etc…) how does your compiler know which one to use? Generally, a compiler will pick a standard to default to. Typically the default is not the most recent language standard — many default to C++14, which …
