The posts General Loop Statements in Modern C++ and Range-for-statement in modern C++ cover ways to write explicit loops. But explicit loops can be tedious to write and, what is more important, – harder to read, because the resulting code requires to spend the extra time by others in order to understand what is going on in the explicit loop. As alternative, the C++ standard library provides…
Each loop statement in C++ has its loop body which is executed repeatedly until the loop condition expression that yields a loop condition becomes false (otherwise, the loop will run “forever”). The statement continue can be used to interrupt the current…
The C++ language provides the switch statement which can be used to replace the set of if statements (see If Statements in Modern C++). First of all, let’s define the enum type Traffic_light_color as follows:
enum class Traffic_light_color { red, yellow, green…
Every implementation of the C++ Standard Library like one included to Embarcadero RAD Studio C++ compilers provides two ways for (pseudo-)random numbers generation: old-fashioned facilities from <cstdlib> and modern facilities provided by <random>.
Facilities from <cstdlib>
There are two very simple functions provided by the C random library: std::srand() and std::rand().
The iterator library that is part of the C++ Standard Library provides the following helpers for writing generic code:
#include <iterator> // helpers are defined here
template<class Container>
void foo(Container& c)
{
// Generic way to obtain (constant)…
Since C++11 there are elegant way to access each element of a containers (or, more generally, sequences) – so called range-for-statement. The syntaxes are follow:
template<class Container>
void foo(Container& container)
{
for (auto element : container)…
Let’s slightly modify the example from The Move Iterator Adapter in C++ post:
#include <algorithm>
#include <list>
#include <string>
#include <vector>
/// @warning BUG! PLEASE, DON'T USE!
auto deep_copy_to_list(const std::vector<std::string>& src)
{
std::list<std::string> dst; // constructs the empty list
copy(cbegin(src), cend(src)…
The dereference prefix operator * being applied to iterator returns the lvalue reference to the element pointed by the iterator. Therefore, algorithms such as std::copy or std::transform calls copying constructors of processed elements, for example:
#include…
By using bidirectional iterator or random access iterator (see Iterator Categories in C++) it’s possible to traverse the sequence in backward direction by using operator -- or by using the special adapter template class std::reverse_iterator. But why to bother with…
Conceptually, iterators are consists of five categories:
input iterator is intended to traverse sequences in the forward direction and provides the read access to the pointed sequence element;output iterator is intended to traverse sequences in the forward direction and provides the write access to the pointed sequence element;forward iterator is intended to traverse sequences in the forward…
