广州做贸易网站,建设网站是做手机版好还是pc版好,网站建设功能解说,做网站的控件C自学精简教程 目录(必读)
该 Vector 版本特点
这里的版本主要是使用模板实现、支持随机访问迭代器#xff0c;支持std::sort等所有STL算法。(本文对随机迭代器的支持参考了 复旦大学 大一公共基础课C语言的一次作业)
随机访问迭代器的实现主要是继承std::iteratorstd:…C自学精简教程 目录(必读)
该 Vector 版本特点
这里的版本主要是使用模板实现、支持随机访问迭代器支持std::sort等所有STL算法。(本文对随机迭代器的支持参考了 复旦大学 大一公共基础课C语言的一次作业)
随机访问迭代器的实现主要是继承std::iteratorstd::random_access_iterator_tag, T来实现的。
随机访问迭代器最牛逼的两个接口是
friend iterator operator(const iterator lhs, size_t n);
friend iterator operator-(const iterator lhs, size_t n);
问题解答
1 为何下面代码中的iterator是struct而不是class
答参考struct与class
题目代码
头文件 Vector.h
#ifndef VEC_H
#define VEC_H
#include iostream
#include cassert
#include initializer_list
//------下面的代码是用来测试你的代码有没有问题的辅助代码你无需关注------
#include algorithm
#include cstdlib
#include iostream
#include vector
#include utility
using namespace std;
struct Record { Record(void* ptr1, size_t count1, const char* location1, int line1, bool is) :ptr(ptr1), count(count1), line(line1), is_array(is) { int i 0; while ((location[i] location1[i]) i 100) { i; } }void* ptr; size_t count; char location[100] { 0 }; int line; bool is_array false; bool not_use_right_delete false; }; bool operator(const Record lhs, const Record rhs) { return lhs.ptr rhs.ptr; }std::vectorRecord myAllocStatistic; void* newFunctionImpl(std::size_t sz, char const* file, int line, bool is) { void* ptr std::malloc(sz); myAllocStatistic.push_back({ ptr,sz, file, line , is }); return ptr; }void* operator new(std::size_t sz, char const* file, int line) { return newFunctionImpl(sz, file, line, false); }void* operator new [](std::size_t sz, char const* file, int line)
{return newFunctionImpl(sz, file, line, true);
}void operator delete(void* ptr) noexcept { Record item{ ptr, 0, , 0, false }; auto itr std::find(myAllocStatistic.begin(), myAllocStatistic.end(), item); if (itr ! myAllocStatistic.end()) { auto ind std::distance(myAllocStatistic.begin(), itr); myAllocStatistic[ind].ptr nullptr; if (itr-is_array) { myAllocStatistic[ind].not_use_right_delete true; } else { myAllocStatistic[ind].count 0; }std::free(ptr); } }void operator delete[](void* ptr) noexcept { Record item{ ptr, 0, , 0, true }; auto itr std::find(myAllocStatistic.begin(), myAllocStatistic.end(), item); if (itr ! myAllocStatistic.end()) { auto ind std::distance(myAllocStatistic.begin(), itr); myAllocStatistic[ind].ptr nullptr; if (!itr-is_array) { myAllocStatistic[ind].not_use_right_delete true; } else { myAllocStatistic[ind].count 0; }std::free(ptr); } }
#define new new(__FILE__, __LINE__)
struct MyStruct { void ReportMemoryLeak() { std::cout Memory leak report: std::endl; bool leak false; for (auto i : myAllocStatistic) { if (i.count ! 0) { leak true; std::cout leak count i.count Byte , file i.location , line i.line; if (i.not_use_right_delete) { cout , not use right delete. ; } cout std::endl; } }if (!leak) { cout No memory leak. endl; } }~MyStruct() { ReportMemoryLeak(); } }; static MyStruct my; void check_do(bool b, int line __LINE__) { if (b) { cout line: line Pass endl; } else { cout line: line Ohh! not passed!!!!!!!!!!!!!!!!!!!!!!!!!!! endl; exit(0); } }
#define check(msg) check_do(msg, __LINE__);
//------上面的代码是用来测试你的代码有没有问题的辅助代码你无需关注------templatetypename T
class Vector
{
public:/* 提供默认构造函数 否则只能使用有参版本这会带来不变例如Vectorint arr; 这样会报错因为需要默认构造函数*/Vector(void);//如果类提供了非默认构造函数编译器不会自动提供默认构造函数Vector(const Vector from);// 复制构造函数Vector(T* start, T* end);// 非默认构造函数Vector(int count, int value);//2 非默认构造函数Vector(std::initializer_listT value_array){for (auto item : value_array){push_back(item);}}Vector operator (const Vector from);bool operator(const Vector other) const{//(1) your codereturn false;}//赋值操作符~Vector();//析构函数
public:int size(void) const;bool empty(void) const;const T operator[] (size_t n) const;T operator[] (size_t n);void push_back(const T val);void clear(void);
private:void deep_copy_from(const VectorT from);public:struct iterator : std::iteratorstd::random_access_iterator_tag, T{friend class Vector;friend bool operator (const iterator lhs, const iterator rhs) { return lhs.m_hold rhs.m_hold; }friend bool operator ! (const iterator lhs, const iterator rhs) { return !(lhs rhs); }friend size_t operator - (const iterator lhs, const iterator rhs) { return lhs.m_hold - rhs.m_hold; }friend bool operator (const iterator lhs, const iterator rhs) { return lhs.m_hold rhs.m_hold; }friend bool operator (const iterator lhs, const iterator rhs) { return lhs.m_hold rhs.m_hold; }friend bool operator (const iterator lhs, const iterator rhs) { return !(lhs rhs); }friend bool operator (const iterator lhs, const iterator rhs) { return !(lhs rhs); }friend iterator operator (const iterator lhs, size_t n) { iterator itr; itr.m_hold lhs.m_hold n; return itr; }//随机访问迭代器牛逼的地方friend iterator operator - (const iterator lhs, size_t n) { iterator itr; itr.m_hold lhs.m_hold - n; return itr; }//随机访问迭代器牛逼的地方public://用于前置形式iterator operator() { m_hold m_hold 1; return *this; };iterator operator--() { m_hold m_hold - 1; return *this; };//用于后置形式iterator operator(int) { iterator itr *this; m_hold 1; return itr; }iterator operator--(int) { iterator itr *this; m_hold - 1; return itr; }T operator*() const//这里必须是const in C14{return *m_hold;}private:T* m_hold;};struct const_iterator : std::iteratorstd::random_access_iterator_tag, T{friend class Vector;friend bool operator (const const_iterator lhs, const const_iterator rhs) { return lhs.m_hold rhs.m_hold; }friend bool operator ! (const const_iterator lhs, const const_iterator rhs) { return !(lhs rhs); }friend size_t operator - (const const_iterator lhs, const const_iterator rhs) { return lhs.m_hold - rhs.m_hold; }friend bool operator (const const_iterator lhs, const const_iterator rhs) { return lhs.m_hold rhs.m_hold; }friend bool operator (const const_iterator lhs, const const_iterator rhs) { return lhs.m_hold rhs.m_hold; }friend bool operator (const const_iterator lhs, const const_iterator rhs) { return !(lhs rhs); }friend bool operator (const const_iterator lhs, const const_iterator rhs) { return !(lhs rhs); }friend const_iterator operator (const const_iterator lhs, size_t n) { const_iterator itr; itr.m_hold lhs.m_hold n; return itr; }//随机访问迭代器牛逼的地方friend const_iterator operator - (const const_iterator lhs, size_t n) { const_iterator itr; itr.m_hold lhs.m_hold - n; return itr; }//随机访问迭代器牛逼的地方public://用于前置形式const_iterator operator() { m_hold m_hold 1; return *this; };const_iterator operator--() { m_hold m_hold - 1; return *this; };//用于后置形式const_iterator operator(int) { const_iterator itr *this; m_hold 1; return itr; }const_iterator operator--(int) { const_iterator itr *this; m_hold - 1; return itr; }const T operator*() const{return *m_hold;}private:T* m_hold;};iterator begin() noexcept{iterator itr;itr.m_hold empty() ? nullptr : m_data[0];return itr;}const_iterator cbegin() const noexcept;iterator end() noexcept{iterator itr;itr.m_hold empty() ? nullptr : m_data[m_size];return itr;}const_iterator cend() const noexcept;
private:size_t m_size 0;//当前元素数量size_t m_capacity 0;//容量T* m_data nullptr;//数据部分
};templatetypename T
VectorT::Vector(void)
{
}templatetypename T
VectorT::Vector(T * start, T * end)
{std::cout Vector(T* start, T* end) std::endl;assert(start ! nullptr end ! nullptr);m_capacity m_size ((size_t)end - (size_t)start)/sizeof(T);//这里如果用int来存放可能会盛不下size_t可以保证盛放的下assert(m_size 0);m_data new T[m_size];for (size_t i 0; i m_size; i){m_data[i] *start;}
}
templatetypename T
VectorT::Vector(int count, int value)
{std::cout Vector(count, value) std::endl;if (count 0){throw std::runtime_error(size of vector to init must bigger than zero!);}m_data new T[count];for (int i 0; i count; i){m_data[i] value;}m_capacity m_size count;
}
templatetypename T
VectorT VectorT::operator(const VectorT from)
{std::cout Vector::operator std::endl;if (this from){return *this;}//先释放自己的数据clear();deep_copy_from(from);return *this;
}templatetypename T
VectorT::~Vector()
{//(2) your code}
templatetypename T
int VectorT::size(void) const
{return m_size;
}
templatetypename T
bool VectorT::empty(void) const
{//(3) your codereturn false;//此处需要修改。
}
templatetypename T
const T VectorT::operator[](size_t n) const
{//(4) your codestatic T t;//此处需要修改。return t;//此处需要修改。
}
templatetypename T
T VectorT::operator[](size_t n)
{//(4) your codestatic T t;//此处需要修改。return t;//此处需要修改。
}
templatetypename T
void VectorT::push_back(const T val)
{//(5) your code}templatetypename T
void VectorT::clear(void)
{//(6) your code
}templatetypename T
void VectorT::deep_copy_from(const VectorT from)
{//(7) your code}templatetypename T
VectorT::Vector(const Vector from)
{//(8) your code}templatetypename T
typename VectorT::const_iterator VectorT::cend() const noexcept
{const_iterator itr const_iterator();//(9) your codereturn itr;
}templatetypename T
typename VectorT::const_iterator VectorT::cbegin() const noexcept
{const_iterator itr const_iterator();//(10) your codereturn itr;
}#endif测试代码main.cpp
#include iostream
#include algorithm
#include Vector.h
#include vectortemplatetypename T
void print(const VectorT v, const std::string msg)
{std::cout The contents of msg.c_str() are:;for (int i 0; i v.size(); i){std::cout v[i];}std::cout \n;
}
templatetypename T
void print_itr(VectorT v, const std::string msg)
{std::cout The contents of msg.c_str() are:;for (auto itr v.begin(); itr ! v.end(); itr){std::cout *itr;}std::cout \n;
}
templatetypename T
void print_const_itr(const VectorT v, const std::string msg)
{std::cout The contents of msg.c_str() are:;for (auto itr v.cbegin(); itr ! v.cend(); itr){std::cout *itr;}std::cout \n;
}int main()
{Vectorint a;Vectorint first; // empty vector of intscheck(first.empty() true);check(first.size() 0);Vectorint second(4, 100); // four ints with value 100check(second.empty() false);check(second.size() 4);check(*second.begin() 100);Vectorint fourth(second); // a copy of thirdcheck(fourth.size() second.size());int myints[] { 16,2,77,29 };Vectorint fifth(myints, myints sizeof(myints) / sizeof(int));check(fifth.empty() false);check(fifth[0] 16);check(fifth[3] 29);check(fifth.size() sizeof(myints) / sizeof(int));print(fifth, fifth);//The contents of fifth are:16 2 77 29 fifth.push_back(30);check(fifth[4] 30);check(fifth.size() 5);print(fifth, fifth);//The contents of fifth are:16 2 77 29 30 check(fifth.size() sizeof(myints) / sizeof(int) 1);first fifth fifth;print(first, first);//The contents of first are:16 2 77 29 30 check(first.empty() false first.size() fifth.size());print_itr(fifth, fifth);//The contents of fifth are:16 2 77 29 30 print_const_itr(fifth, fifth);//The contents of fifth are:16 2 77 29 30 std::sort(fifth.begin(), fifth.end());std::cout fifith after sort: std::endl;print_const_itr(fifth, fifth);//The contents of fifth are:16 2 77 29 30 Vectorint a1(myints, myints sizeof(myints) / sizeof(int));{Vectorint b(a1);b.push_back(2);check(b[4] 2);auto result (b Vectorint{ 16, 2, 77, 29, 2});check(result);//iteratorcheck(b.begin() b.size() b.end());auto begin b.begin();auto itr b.begin() 1;check(*begin 16);check(*itr 2);}{Vectorint b{ 1,3,5,7 };b.push_back(9);}{Vectorint c;for (auto i : c){std::cout i ;}c a1;for (auto i : c){std::cout i ;}std::cout std::endl;}check(a1.size() sizeof(myints) / sizeof(int));{Vectorint c;c fifth;c[0] 1;check(c[0] 1);}
} 预期输出
line:42 Pass
line:43 Pass
Vector(count, value)
line:45 Pass
line:46 Pass
line:47 Pass
line:49 Pass
Vector(T* start, T* end)
line:53 Pass
line:54 Pass
line:55 Pass
line:56 Pass
The contents of fifth are: 16 2 77 29
line:59 Pass
line:60 Pass
The contents of fifth are: 16 2 77 29 30
line:62 Pass
Vector::operator
Vector::operator
The contents of first are: 16 2 77 29 30
line:65 Pass
The contents of fifth are: 16 2 77 29 30
The contents of fifth are: 16 2 77 29 30
fifith after sort:
The contents of fifth are: 2 16 29 30 77
Vector(T* start, T* end)
line:75 Pass
line:77 Pass
line:80 Pass
line:83 Pass
line:84 Pass
Vector::operator
16 2 77 29
line:103 Pass
Vector::operator
line:108 Pass
Memory leak report:
No memory leak.
