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C++入门自学Day11-- String, Vector, List 复习

news 2025/8/18 17:13:01

往期内容回顾

     List类型的自实现

   List类型（初识）

Vector类的自实现

     Vector类（注意事项）

          初识Vector

    String类的自实现

         String类的使用（续）

         String类（续）

         String类（初识）

一、String类型的自实现

1、string基本结构-- 构造，析构函数，成员变量

class my_string{
public://列表的初始化，析构函数my_string():_str(nullptr),_size(0),_capacity(0){cout<<"using Constructor: "<<endl;}void clean(){delete _str;_size = 0;_capacity = 0;}~my_string(){clean();_str = nullptr;cout<<"using Deonstructor: "<<endl;}private:char* _str;size_t _size;size_t _capacity;
};

测试函数
void test1(){my_string s1;
}
输出：

using Constructor:
using Deonstructor:

2、string的基本属性--> size, capacity, empty

size_t size()const{return _size;
}
size_t capacity()const{return _capacity;
}
bool empty(){return bool(size() == 0);
}

测试函数：

void test2(){my_string s1;cout<<s1.capacity()<<endl;cout<<s1.size()<<endl;cout<<s1.empty()<<endl;
}

输出描述：

using Constructor:
0
0
1
using Deonstructor:

3、内存管理函数：resize，reserve实现

void reserve(size_t n){if(n > capacity()){char* tmp =  new char[n+1]; // memcpy(tmp,_str,size());if(_str){strcpy(tmp,_str);delete[] _str;}_str = tmp;_capacity = n;}
}
void resize (size_t n, char c = '\0'){size_t sz = size();if(n > size()){if(n>capacity()){reserve(n);}while (sz!= n){_str[sz++] = c;}}_str[n] = '\0';_size = n;
}

测试函数：

void test3(){my_string s1;s1.reserve(4);cout<<s1.capacity()<<endl;s1.resize(10,'g');Print_string(s1);

输出描述：

using Constructor:
4
g g g g g g g g g g
using Deonstructor:

4、string类的增删查改

   //增删查改void push_back (char c){if(_size == _capacity){//增容size_t new_capacity = (_capacity == 0)?2: 2*_capacity;reserve(new_capacity);}_str[_size] = c;++_size;}my_string& insert (size_t pos, const char c){assert(pos <= size());if(_size == _capacity){//增容size_t new_capacity = (_capacity == 0)?2: 2*_capacity;reserve(new_capacity);}size_t end = size();while (end >= pos){_str[end+1] = _str[end];if(end == 0){break;}--end;};++_size;_str[pos] = c;_str[_size] = '\0';return *this;};my_string&  insert(size_t pos, const char* str){assert(pos <= size());size_t len  = strlen(str);size_t sz = len + size();if(sz > capacity()){reserve(sz);}size_t end = size();while (end >= pos){_str[end+len] = _str[end];if(end == 0){break;}--end;};// strncpy()for(size_t i = 0;i< len;i++){_str[pos+i] = str[i];};_size = sz;_str[_size] = '\0';return *this;}// void insert(size_t pos, const my_string& str);my_string& append (const char* s){size_t sz = strlen(s);size_t num = sz + size();if(num > capacity()){reserve(num);}strcat(_str,s);_size = num;return *this;}my_string& erase (size_t pos = 0, size_t len = npos){assert(pos < size());size_t sz = size();if(pos + len >= sz){_size = pos;}else{size_t write = pos;size_t read = pos + len;while ( _str[read] != '\0'){_str[write++] = _str[read++];}_size = sz-len;_str[_size] = '\0';}return *this;}size_t find(char ch, size_t pos = 0){assert(pos < size());while (pos < size()){if(_str[pos] == ch){return pos;}++pos;}return npos;};size_t find(const char* str, size_t pos = 0){assert(pos < size());while (pos < size()){if(_str[pos] == str[0]){size_t len = strlen(str);size_t index;for(index = 1;index<len;index++){if(str[index] != _str[pos+index]){break;} }if(index == len){return pos;}}++pos;}return npos;}

测试代码：

void test4(){my_string s1;s1.push_back('a');s1.push_back('b');s1.push_back('c');s1.append("def");s1.insert(0,'x');Print_string(s1);s1.erase(3,2);Print_string(s1);size_t ind = s1.find("xa");cout<< "index = " << ind<<endl;

输出描述：

using Constructor:
x a b c d e f
x a b e f
index = 0
using Deonstructor:

5、赋值运算符和拷贝构造

    my_string(const my_string& s1){if(this != &s1){char* tmp = new char[s1._capacity+1];memcpy(tmp,s1._str,s1._size);_str = tmp;_capacity = s1._capacity;_size = s1._size;}};my_string& operator = (my_string s1){::swap(_str,s1._str);_size = s1._size;_capacity = s1._capacity;return *this;}

测试函数：

void test5(){my_string s1;s1.push_back('a');s1.push_back('b');s1.push_back('c');my_string s2(s1);Print_string(s2);my_string s3;s3 = s2;Print_string(s3);
}

输出描述：

using Constructor:
a b c
using Constructor:
using Deonstructor:
a b c
using Deonstructor:
using Deonstructor:
using Deonstructor:

6、遍历运算符重载

    char& operator[](size_t i){assert(i<_size);return _str[i];}const char& operator[](size_t i) const{assert(i<_size);return _str[i];}

测试代码：

void test6(){my_string s1;s1.append("abcdef");for(size_t i = 0; i<s1.size();i++){cout<< s1[i]<<" ";}cout<<endl;

输出描述：

using Constructor:
a b c d e f
using Deonstructor:

二、Vector类型的自实现

1、Vector基本结构-- 构造，析构函数，成员变量

#include<iostream>
#include<assert.h>
using namespace std;
template <typename T>
class my_vector{
public:my_vector():_start(nullptr),_finish(nullptr),_endofstorage(nullptr){cout<<"Using Constructor!"<<endl;}~my_vector(){cout<<"Using Destructor!"<<endl;delete[] _start;_start = nullptr;_finish = nullptr;_endofstorage = nullptr;}
private:T* _start;T* _finish;T* _endofstorage; 
};

测试函数：

void test1(){my_vector<int> v;
}

输出描述：

Using Constructor!

Using Destructor!

2、Vector的基本属性--> size, capacity, empty

size_t size()const {return _finish - _start;
}size_t capacity()const {return _endofstorage - _start;
}
bool empty(){if(_start == _finish){return true;}return false;
}

测试函数：

void test2(){my_vector<int> v;v.push_back(1);cout<< v.capacity()<<endl;v.push_back(2);v.push_back(3);v.push_back(4);cout<< v.capacity()<<endl;if(v.empty()){cout<< "Vector is not empty!"<<endl;}Print_vector(v);
}

输出描述：

2
4
Vector is not empty!
1 2 3 4

3、内存管理函数：resize，reserve实现

void reserve(size_t n){size_t sz = size();if(n > capacity()){T* tmp = new T[n];if(_start){std::copy(_start,_finish,tmp);delete[] _start;}_start = tmp;_finish = _start +sz;_endofstorage = _start + n;}
}
void resize(size_t n, const T& val){size_t sz = size();if(n <= sz){_finish  = _start + n;}else{if(n > capacity()){reserve(n);}while (_finish != _endofstorage){*_finish = val;++_finish;}}
}

测试函数：

void test2(){my_vector<int> v;v.push_back(1);v.reserve(10);cout<<"capacity is "<<v.capacity()<<endl;v.push_back(2);v.push_back(3);v.push_back(4);v.resize(12,5);Print_vector(v);
}

输出描述：

capacity is 10
1 2 3 4 5 5 5 5 5 5 5 5

4、string类的增删查改

void push_back(const T& x){// if(_finish == _endofstorage){//     //增容//     size_t new_capacity = (capacity() == 0)? 2 : 2* capacity();//     reserve(new_capacity);// }// *_finish = x;// ++_finish;insert(_finish,x);
}
void pop_back(){erase(_finish-1);
}iterator insert (iterator position, const T& val){assert(position <= _finish && _start <= position);if(_finish == _endofstorage){size_t num = position - _start;size_t new_capacity = (capacity() == 0) ? 2 : 2*capacity();reserve(new_capacity);position = _start + num;}for(T* end = _finish; end > position; --end){*end = *(end-1);};*position = val;++_finish;return position;
}
iterator erase (iterator pos){assert(pos < _finish && _start <= pos);if(_start != _finish){T* _init = pos;for(T* _init = pos;_init < _finish-1;++_init){*(_init) = *(_init + 1);} --_finish;}return pos;
}
iterator erase (iterator first, iterator last){assert(first >= _start && last <= _finish && _start);size_t num = last - first;size_t res = _finish - last;T* end = last;T* begin = first;while (res--){*begin = *end;++end;++begin;}_finish -= num;return first;
}

测试函数：

void test3(){my_vector<int> v;v.push_back(1);v.push_back(2);v.push_back(3);v.push_back(4);v.insert(v.begin(),0);Print_vector(v);v.insert(v.end(),5);Print_vector(v);v.erase(v.begin());Print_vector(v);v.erase(v.begin(),v.end());Print_vector(v);
}

输出描述：

0 1 2 3 4
0 1 2 3 4 5
1 2 3 4 5

5、赋值运算符和拷贝构造

my_vector(const my_vector<T>& v){if(this != &v){size_t new_capacity = v.capacity();T* tmp = new T[v.capacity()];::copy(v._start,v._finish,tmp);_start = tmp;_finish = _start + v.size();_endofstorage = _start+new_capacity;};
}my_vector<T>& operator = (my_vector<T> v){swap(v);return *this;
}

测试函数：

void test4(){my_vector<int> v;v.push_back(1);v.push_back(2);v.push_back(3);v.push_back(4);my_vector<int> v2;v2 = v;Print_vector(v2);
}

输出描述：

1 2 3 4

6、遍历运算符重载

typedef T* iterator;
typedef T* const_iterator;iterator begin(){return _start;
}
iterator end(){return _finish;
}const_iterator begin()const{return _start;
}
const_iterator end()const{return _finish;
}template <typename T>
void Print_vector(const my_vector<T> & v){typename my_vector<T>::const_iterator it = v.begin();while (it != v.end()){cout<< *it <<" ";++it;}cout<< endl;
}

三、List类型的自实现

1、List基本结构-- 构造，析构函数，成员变量

#include<iostream>
#include<assert.h>
using namespace std;template<typename T>
struct ListNode
{ListNode* prev;ListNode* next;T data;ListNode(const T& val = T()):prev(nullptr),next(nullptr),data(val){}
};template<typename T>
class mylist
{typedef ListNode<T> Node;
public:mylist():head(new ListNode<T>()) //自动调用构造函数{   cout<<"Using Constructor!"<<endl;head->next = head;head->prev = head;}void clear(){Node* cur = head->next;while (cur != head){Node* Next = cur->next;delete cur;cur = Next;}head->prev = head;head->next = head;}~mylist(){cout<<"Using Destructor!"<<endl;clear();delete head;head = nullptr;}
private:Node* head;
};

测试函数：

void test1(){mylist<string> l1;cout<<"size = "<<l1.size()<<endl;if(l1.empty()){cout<<"List l1 is empty!"<<endl;}}

输出描述：

Using Constructor!

Using Destructor!

2、List的基本属性--> size, empty

size_t size(){size_t num = 0;Node* cur = head->next;while (cur != head){++num;cur = cur -> next;}return num;
}
bool empty(){return(head == head->next &&head == head->prev);
}

测试函数：

void test1(){mylist<string> l1;cout<<"size = "<<l1.size()<<endl;if(l1.empty()){cout<<"List l1 is empty!"<<endl;}}

输出描述：

Using Constructor!
size = 0
List l1 is empty!
Using Destructor!

3、List的专属迭代器实现

template<class T, class Ref, class Ptr>
struct list_iterator
{typedef ListNode<T> Node;Node* _node;typedef list_iterator<T,Ref,Ptr> Self;list_iterator(Node* node = nullptr):_node(node){}Ref operator *(){return _node->data;}Ptr operator->(){return &(_node->data);}Self& operator++(){_node = _node->next;return *this;}Self operator++(int){list_iterator tmp = *this;++(*this);return tmp;}Self& operator--(){_node = _node ->prev;return *this;}Self operator--(int){list_iterator tmp = _node;--(*this);return tmp;}bool operator ==(const Self& it){return(_node == it._node);}bool operator !=(const Self& it){return !(_node == it._node);}
}typedef list_iterator<T,T&,T*> iterator;typedef list_iterator<T,const T&,const T*> const_iterator;iterator begin(){return head->next;}iterator end(){return head;}const_iterator begin()const{return head->next;}const_iterator end()const{return head;}

测试函数：

template<typename T>
void Print_List(const mylist<T>& l1){   typename mylist<T>::const_iterator it = l1.begin();while (it != l1.end()){cout<< *it << " ";++it;}cout<<endl;

4、List类的增删查改, 拼接

    T& front(){return (head->next)->data;}T& back(){return (head->prev)->data;}void push_front(const T& val){Node* newnode = new Node(val);Node* cur = head->next;head->next = newnode;newnode->prev = head;cur->prev = newnode;newnode->next = cur;}void push_back(const T& val){Node* newnode = new Node(val);Node* last = head->prev;head->prev = newnode;newnode->next = head;last->next = newnode;newnode->prev = last;}iterator insert(iterator position, const T& val) {Node* cur = position._node;  // 要插入的位置Node* newnode = new Node(val);Node* Prev = cur->prev;newnode->next = cur;newnode->prev = Prev;Prev->next = newnode;cur->prev = newnode;return iterator(newnode); // 返回新节点的迭代器
}iterator erase(iterator position) {assert(position != end());Node* cur = position._node;Node* Prev = cur->prev;Node* Next = cur->next;Prev->next = Next;Next->prev = Prev;delete cur;return iterator(Next); // 返回删除节点之后的位置
}
void splice (iterator position, mylist& x){if(x.empty()) return;Node* cur = position._node;Node* Prev = cur->prev;Prev->next = x.head->next;(x.head->next)->prev = Prev;cur->prev = x.head->next;(x.head->prev)->next = cur;x.head->next = x.head;x.head->prev = x.head;}

5、赋值运算符和拷贝构造

mylist(const mylist<T>& l1){head = new Node();head->_next = head;head->_prev = head;const_iterator start = l1.begin();while (start!= l1.end()){push_back(start._node->_data);++start;}        }