文章目录
- 一、string类的模拟实现
- 1、构造、拷贝构造、赋值运算符重载以及析构函数
- 2、迭代器类
- 3、增删查改类
- 4、io类
- 5、扩容类
- 6、完整代码
一、string类的模拟实现
1、构造、拷贝构造、赋值运算符重载以及析构函数
2、迭代器类
3、增删查改类
4、io类
5、扩容类
6、完整代码
namespace bit
{class string{public:typedef char* iterator;typedef const char* const_iterator;const_iterator beagin() const{return _str;}const_iterator end() const{return _str + _size;;}iterator begin(){return _str;}iterator end(){return _str + _size;}void insert(size_t pos, char ch){assert(pos <= _size);if (_size == _capacity){reserve(_capacity == 0 ? 4 : _capacity *= 2);}size_t end = _size + 1;while (end >pos){_str[end] = _str[end-1];end--;}_str[pos] = ch;_size++;}void insert(size_t pos, const char* ch){assert(pos <= _size);size_t len = strlen(ch);if (_size + len > _capacity){reserve(_size + len);}size_t end = _size;while (end > pos){_str[end + len] = _str[end];--end;}strncpy(_str + pos, ch, len);_size += len; }void erase(size_t pos, size_t len = npos){assert(pos < _size);if (len == npos || pos + len > _size){_str[pos] = '\0';_size = pos;}else{size_t begin = _size + len;while (begin <= _size){_str[pos++] = _str[begin++];}_size -= len;}}void push_back(char ch){if (_size == _capacity){reserve(_capacity == 0 ? 4 : _capacity * 2);}_str[_size] = ch;++_size;_str[_size] = '\0';}void append(const char* str){size_t len = strlen(str);if (_size + len > _capacity){reserve(_size + len);strcpy(_str + _size, str);_size += len;}}string& operator+=(char ch){push_back(ch);return *this;}string& operator+=(const char* ch){append(ch);return *this;}string(const char* str = ""):_size(strlen(str)),_capacity(_size){_str = new char[_size + 1];strcpy(_str, str);}~string(){delete[] _str;_str = nullptr;_size = 0;_capacity = 0;}string(const string& s):_str(nullptr), _size(0), _capacity(0){string tmp(s._str);swap(tmp);}string& operator=(string s){swap(s);return *this;}void reserve(size_t n){if (n > _capacity){char* tmp = new char[n + 1];strcpy(tmp, _str);_str = tmp;_capacity = n;}}void resize(size_t n,char ch='\0'){if (n <= _size){_str[n] = ch;_size = n;}else{reserve(n);while (_size < n){_str[_size++] = ch;}_str[_size] = '\0';}}void clear(){_str[0] = '\0';_size = 0;}void swap(string& s){std::swap(_str, s._str);std::swap(_size, s._size);std::swap(_capacity, s._capacity);}size_t find(char ch, size_t pos = 0){for (size_t i = pos; i < _size; i++){if (_str[i] == ch){return i;}}return npos;}size_t find(const char* sub, size_t pos=0){const char* p = strstr(_str + pos, sub);if (p){return p - _str;}else{return npos;}}string substr(size_t pos, size_t len = npos){string s;size_t end = pos + len;if (len == npos || pos + len >= _size){len = _size - pos;end = _size;}s.reserve(len);for (size_t i = pos; i <= end; i++){s += _str[i];}return s;}private:char* _str;size_t _size;size_t _capacity;const static size_t npos;};const size_t string::npos = -1;ostream& operator<< (ostream& out, string& s){for (auto ch : s){out << ch;}return out;}istream& operator>> (istream& in, string& s){s.clear();char buff[129];size_t i = 0;char ch;ch = in.get();while (ch != ' ' && ch != '\0'){buff[i++] = ch;if (i == 128){buff[i] = '\0';s += buff;i = 0;}s += ch;ch = in.get();}if (i != 0){buff[i] = '\0';s += buff;}return in;}}
