In lesson , we discussed arrays and enumerations. Now that we have constexpr std::array in our toolkit, we’re going to continue that discussion and show a few additional tricks. Using static assert to ensure the proper number of array initializers When initializing a constexpr std::array using CTAD, the compiler will …
In the prior lesson, we mentioned that arrays can have elements of any object type. This includes objects with fundamental types (e.g. int) and objects with compound types (e.g. pointer to int). #include <array> #include <iostream> #include <vector> int main() { int x { 1 }; int y { 2 …
A std::array isn’t limited to elements of fundamental types. Rather, the elements of a std::array can be any object type, including compound types. This means you can create a std::array of pointers, or a std::array of structs (or classes) However, initializing a std::array of structs or classes tends to trip …
An object of type std::array can be passed to a function just like any other object. That means if we pass a std::array by value, an expensive copy will be made. Therefore, we typically pass std::array by (const) reference to avoid such copies. With a std::array, both the element type …
In lesson , we discussed the unfortunate decision to make the standard library container classes use unsigned values for lengths and indices. Because std::array is a standard library container class, it is subject to the same issues. In this lesson, we’ll recap ways to index and get the length of …
Words of encouragement This chapter isn’t an easy one. We covered a lot of material, and unearthed some of C++’s warts. Congrats on making it through! Arrays are one of the keys that unlock a huge amount of power within your C++ programs. Chapter Review A container is a data …
In lesson , we discussed how std::bitset has the capability to compact 8 Boolean values into a byte. Those bits can then be modified via the member functions of std::bitset. std::vector has an interesting trick up its sleeves. There is a special implementation for std::vector<bool> that may be more space …
Consider the case where you are writing a program where the user will enter a list of values (such as a bunch of test scores). In this case, the number of values that they will be entering is not known at compile time, and could vary every time they run …
One of the bigger documentation problems with arrays is that integer indices do not provide any information to the programmer about the meaning of the index. Consider an array holding 5 test scores: #include <vector> int main() { std::vector testScores { 78, 94, 66, 77, 14 }; testScores[2] = 76; …
In lesson , we noted how we generally prefer to use signed values to hold quantities, because unsigned values can act in surprising ways. However, in lesson , we discussed how std::vector (and other container classes) uses unsigned integral type std::size_t for length and indices. This can lead to problems …
