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#include <iostream>
#include <cassert>
#include <cstring>
#include <cstdlib>
#include <functional>
#include <type_traits>
#include <cstdint>
#include <vector>
#include <map>
#include <memory>
#include <regex>
// Functional programming
// Function that returns a callable in the form of a lambda
std::function<int (int)> make_adder(int x)
{
return ([=](int a) -> int{ return x + a; });
}
void do_functional()
{
// Lambda with no capture
auto simple_lambda = [](int a){ return a + 3; };
assert(simple_lambda(5) == 8);
// Capture by value
int x = 5;
auto by_value = [x](int a){ return a + x; };
assert(by_value(1) == 6);
x = 7; // change not seen by lambda
assert(by_value(1) == 6);
// Also >> at end of template
assert((std::is_convertible<decltype(by_value),
std::function<int(int)>>::value));
// Capture by reference
auto by_reference = [&x](int a){ return a + x; };
assert(by_reference(1) == 8);
x = 8; // change seen my lambda
assert(by_reference(1) == 9);
// Get a callable from a function
auto add3 = make_adder(3);
assert(add3(5) == 8);
auto make_addr_lambda = [](int a) {
return [a](int b) { return a + b; };
};
assert(make_addr_lambda(6)(8) == 14);
// nullptr and {} are empty functions
std::function<void()> f1 = {};
assert(! f1);
std::function<void()> f2 = nullptr;
assert(! f2);
}
// Integer types, type traits
template <typename T>
void check_size(size_t size, bool is_signed)
{
assert(sizeof(T) == size);
assert(std::is_signed<T>::value == is_signed);
}
void do_inttypes()
{
// static_assert is a compile-time check
static_assert(1 == sizeof(int8_t), "int8_t check");
check_size<int8_t>(1, true);
check_size<uint8_t>(1, false);
check_size<int16_t>(2, true);
check_size<uint16_t>(2, false);
check_size<int32_t>(4, true);
check_size<uint32_t>(4, false);
check_size<int64_t>(8, true);
check_size<uint64_t>(8, false);
// auto, decltype
auto x = 5LL;
check_size<decltype(x)>(8, true);
assert((std::is_same<long long, decltype(x)>::value));
}
class A
{
public:
static constexpr auto def_value = 5;
A(int x) :
x(x)
{
}
// Constructor delegation
A() : A(def_value)
{
}
int getX() const
{
return x;
}
private:
int x;
};
void do_iteration()
{
// Initializers, foreach syntax, auto for iterators
std::vector<int> v = { 1, 2, 3, 4 };
assert(v.size() == 4);
int sum = 0;
for (auto& i: v)
{
sum += i;
}
assert(10 == sum);
for (auto i = v.begin(); i != v.end(); ++i)
{
sum += *i;
}
assert(20 == sum);
std::vector<A> v2 = { A(), A(3) };
assert(5 == v2.at(0).getX());
assert(3 == v2.at(1).getX());
}
// Variadic template
template<class A1>
void variadic1(A1 const& a1)
{
assert(a1 == 12);
}
template<class A1, class A2>
void variadic1(A1 const& a1, A2 const& a2)
{
assert(a1 == a2);
}
template<class ...Args>
void variadic(Args... args)
{
variadic1(args...);
}
template<class A>
bool pairwise_equal(A const& a, A const& b)
{
return (a == b);
}
template<class T, class ...Rest>
bool pairwise_equal(T const& a, T const& b, Rest... rest)
{
return pairwise_equal(a, b) && pairwise_equal(rest...);
}
void do_variadic()
{
variadic(15, 15);
variadic(12);
assert(pairwise_equal(5, 5, 2.0, 2.0, std::string("a"), std::string("a")));
assert(! pairwise_equal(5, 5, 2.0, 3.0));
}
// deleted, default
class B
{
public:
B(int x) :
x(x)
{
}
B() : B(5)
{
}
int getX() const
{
return x;
}
virtual ~B() = default;
B(B const&) = delete;
B& operator=(B const&) = delete;
private:
int x;
};
void do_default_deleted()
{
B b1;
assert(5 == b1.getX());
assert(std::is_copy_constructible<A>::value);
assert(! std::is_copy_constructible<B>::value);
}
// smart pointers
class C
{
public:
C(int id = 0) :
id(id)
{
incr(id);
}
~C()
{
decr(id);
}
C(C const& rhs) : C(rhs.id)
{
}
C& operator=(C const& rhs)
{
if (&rhs != this)
{
decr(id);
id = rhs.id;
incr(id);
}
return *this;
}
static void check(size_t size, int v, int count)
{
assert(m.size() == size);
auto p = m.find(v);
if (p != m.end())
{
assert(p->second == count);
}
}
private:
void incr(int i)
{
++m[i];
}
void decr(int i)
{
if (--m[i] == 0)
{
m.erase(i);
}
}
static std::map<int, int> m;
int id;
};
std::map<int, int> C::m;
std::shared_ptr<C> make_c(int id)
{
return std::make_shared<C>(id);
}
std::shared_ptr<C> make_c_array(std::vector<int> const& is)
{
auto p = std::shared_ptr<C>(new C[is.size()], std::default_delete<C[]>());
C* pp = p.get();
for (size_t i = 0; i < is.size(); ++i)
{
pp[i] = C(is.at(i));
}
return p;
}
void do_smart_pointers()
{
auto p1 = make_c(1);
C::check(1, 1, 1);
auto p2 = make_c_array({2, 3, 4, 5});
for (auto i: {1, 2, 3, 4, 5})
{
C::check(5, i, 1);
}
{
C::check(5, 1, 1);
C c3(*p1);
C::check(5, 1, 2);
}
C::check(5, 1, 1);
p1 = nullptr;
C::check(4, 1, 0);
p2 = nullptr;
C::check(0, 0, 0);
{
std::unique_ptr<C> p3(new C(6));
C::check(1, 6, 1);
}
C::check(0, 0, 0);
}
// Regular expressions
void do_regex()
{
// Basic match/search. Match matches whole string; search searches
// within string. Use std::smatch for matching std::string and
// std::cmatch for matching char const*.
std::regex expr1("([0-9]+)");
std::regex expr2("([0-9]+)\\s*([a-z]+)[[:space:]]*([0-9]+)");
std::string str1("one 234 fifth 678 nine");
std::string str2("234 five 678 nine");
std::string str3("one 234 five 678");
std::string str4("234");
std::string str5("234 five 678");
std::smatch match1;
assert(! std::regex_match(str1, match1, expr1));
assert(! std::regex_match(str2, match1, expr1));
assert(! std::regex_match(str3, match1, expr1));
assert(std::regex_match(str4, match1, expr1));
assert(match1[0].first == match1[1].first);
assert(match1[0].second == match1[1].second);
std::string s;
s.assign(match1[1].first, match1[1].second);
assert("234" == s);
assert(s == match1[1].str());
assert(std::regex_match(str5, match1, expr2));
assert("234 five 678" == match1[0].str());
assert("234" == match1[1].str());
assert("five" == match1[2].str());
assert("678" == match1[3].str());
assert(std::regex_search(str1, match1, expr2));
assert("234 fifth 678" == match1[0].str());
assert("234" == match1[1].str());
assert("fifth" == match1[2].str());
assert("678" == match1[3].str());
// Iterator
std::regex expr3("[[:digit:]]+");
std::string str6 = "asdf234erasdf9453.kgdl423asdf";
std::sregex_iterator m1(str6.begin(), str6.end(), expr3);
std::sregex_iterator m2;
s.clear();
for (std::sregex_iterator iter = m1; iter != m2; ++iter)
{
std::smatch const& match2 = *iter;
s += match2[0].str() + "|";
}
assert("234|9453|423|" == s);
// Submatches
std::regex expr4("(?:(asdf)|(qwer))");
char const* str7 = "0asdf1qwer2";
std::cregex_iterator m3(str7, str7 + std::strlen(str7), expr4);
assert("asdf" == (*m3)[0].str());
assert((*m3)[1].matched);
assert(! (*m3)[2].matched);
++m3;
assert("qwer" == (*m3)[0].str());
assert(! (*m3)[1].matched);
assert((*m3)[2].matched);
}
static long operator ""_x(char const* v)
{
return strtol(v, nullptr, 16);
}
static std::string operator ""_y(char const* v, size_t len)
{
return "y" + std::string(v, len) + "y";
}
void do_user_defined_literals()
{
assert(10_x == 16); // operator""_x("10")
assert("abc"_y == "yabcy"); // operator""_y("abc", 3)
// Raw literals. Optional matching label before and after ()
// allows embedding something that looks like the default end
// delimiter in the string.
assert(R"(abc)"_y == "yabcy");
// This construct does not work in MSVC as of version 2019.
// assert(R"x(a)"bc)x"_y == "ya)\"bcy");
}
int main()
{
do_functional();
do_inttypes();
do_iteration();
do_variadic();
do_default_deleted();
do_smart_pointers();
do_regex();
do_user_defined_literals();
std::cout << "assertions passed\n";
return 0;
}
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