主要模拟代码
#pragma once #include<iostream> #include<assert.h> using namespace std; namespace ljp { class string { friend void swap(string& s1, string& s2); friend istream& operator>>(istream& in, string& s); friend ostream& operator<<(ostream& out, string& s); public: typedef char* iterator; typedef const char* const_iterator; //构造函数 string(const char*str="") :_size(strlen(str)) { _capacity = _size; _str = new char[_capacity + 1]; strcpy(_str, str); } //析构函数 ~string() { delete[] _str; _str = nullptr; _size = _capacity = 0; } //拷贝构造 string(const string& s) { string tem(s.str()); swap(*this, tem); } //赋值运算符重载 string& operator=(string s) { swap(*this,s); return *this; } //c_str const char* str() const { return _str; } //[]重载 char& operator[](size_t pos) { assert(pos < _size); return _str[pos]; } //const []重载 const char& operator[](size_t pos) const { assert(pos < _size); return _str[pos]; } //begin和end iterator begin() const { return _str; } iterator end() const { return _str + _size; } //size size_t size() const { return _size; } //capacity size_t capacity() const { return _capacity; } //reserve一次开辟一定的空间 void reserve(size_t n) { if (n > _capacity) { char* tem = new char[n + 1]; strcpy(tem, _str); delete[] _str; _str = tem; _capacity = n; } } //pushhu_back void push_back(char ch) { if (_size == _capacity) { reserve(_capacity == 0 ? 4 : _capacity * 2); } _str[_size] = ch; ++_size; _str[_size] = '\0'; } //append void append(const char*str) { //扩容 size_t len = strlen(str); if (_size + len >= _capacity) { reserve(_size + len+1); } strcpy(_str + _size, str); _size += len; } //+=运算符重载 string& operator+=(char ch) { push_back(ch); return *this; } string& operator+=(const char* str) { append(str); return *this; } //insert函数 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* str) { assert(pos <= _size); size_t len = strlen(str); if (_size + len >= _capacity) { reserve(_size + len+1); } size_t end = _size + len; //注意while的判断条件 while (end > pos+len-1) { _str[end] = _str[end - len]; end--; } strncpy(_str + pos, str, len); _size += len; } //erase void earse(size_t pos, size_t len = npos) { assert(pos < _size); if (len == npos || len >= _size-pos) { _str[pos] = '\0'; _size = pos; } else { strcpy(_str + pos, _str + pos + len); _size -= len; } } //resize void resize(size_t n,char ch='\0') { if (n <= _size) { _str[n] = '\0'; _size = n; } else { reserve(n); for (size_t i = _size; i < n; i++) { _str[i] = ch; } _str[n] = '\0'; _size = n; } } //find查找 size_t find(char ch, size_t pos=0)const { assert(pos < _size); for (size_t i = 0; i < _size; i++) { if (_str[i] == ch) return i; } return npos; } size_t find(const char* sub, size_t pos = 0)const { assert(pos < _size); const char* p = strstr(_str + pos, sub); if (p) { return p - _str; } else return npos; } //substr string substr(size_t pos=0, size_t len = npos) { string sub; if (len >= _size - pos) { for (size_t i = pos; i < _size; i++) { sub += _str[i]; } } else { for (size_t i = pos; i < pos + len; i++) { sub += _str[i]; } } return sub; } //clear void clear() { _size = 0; _str[_size] = '\0'; } private: char* _str = nullptr; size_t _size=0; size_t _capacity=0; public: static const int npos; }; const int string::npos = -1; //swap交换 void swap(string& s1,string& s2) { std::swap(s1._str, s2._str); std::swap(s1._size, s2._size); std::swap(s1._capacity, s2._capacity); } ostream& operator<<(ostream& out, string& s) { for (int i = 0; i < s.size(); i++) { out << s[i]; } return out; } istream& operator>>(istream& in, string& s) { s.clear(); char ch; ch = in.get(); char buffer[128]; size_t i = 0; while (ch != ' ' && ch != '\n') { buffer[i++] = ch; if (i == 127) { buffer[127] = '\0'; s += buffer; i = 0; } ch = in.get(); } if (i > 0) { buffer[i] = '\0'; s += buffer; } return in; } istream& getline(istream& in, string& s) { s.clear(); char ch; ch = in.get(); char buffer[128]; size_t i = 0; while (ch != '\n') { buffer[i++] = ch; if (i == 127) { buffer[127] = '\0'; s += buffer; i = 0; } ch = in.get(); } if (i > 0) { buffer[i] = '\0'; s += buffer; } return in; } void test_string1() { string s1("abcdefg"); const string s2("xxxxxxxxxxxx"); cout << s1.str() << endl; cout << s2.str() << endl; } void test_string2() { //string s1("hello world"); const string s1("xxxxxxxxxxxx"); cout << "for循环遍历: "; for (size_t i = 0; i < s1.size(); i++) { //s1[i]++; cout << s1[i]; } cout << endl; cout << "迭代器遍历: "; //string::iterator it1 = s1.begin(); string::const_iterator it2 = s1.begin(); while (it2 != s1.end()) { //--*it; cout << *it2; it2++; } cout << endl; cout << "范围for遍历: "; for (auto i : s1) { cout << i; } cout << endl; } void test_string3() { string s1("hello world"); s1.push_back(' '); s1.push_back('h'); s1.push_back('e'); s1.push_back('l'); s1.push_back('l'); s1.push_back('o'); cout << s1.str() << endl; } void test_string4() { string s1("hello world"); s1.append("lijinpeng"); cout << s1.str() << endl; } void test_string5() { string s1("hello world"); s1 += 'l'; s1 += 'j'; s1 += 'p'; s1 += "xxxxxxxxxx"; cout << s1.str() << endl; } void test_string6() { string s1("hello world"); /*s1.insert(0, 'x'); s1.insert(0, 'x'); s1.insert(0, 'x'); s1.insert(0, 'x');*/ s1.insert(5, "xxxxxxxx"); cout << s1.str() << endl; //s1.earse(2,7); //cout << s1.str() << endl; } void test_string7() { string s1("hello world"); s1.resize(2); cout << s1.str() << endl; string s2("hello world"); s2.resize(17,'x'); cout << s2.str() << endl; } void test_string8() { string s1("hello world"); string s2(s1); string s3 = s1; cout << s1.str() << endl; cout << s2.str() << endl; cout << s3.str() << endl; } void test_string9() { string s1("hello world"); string s2("lijinpeng"); cout << s1.str() << endl; cout << s2.str() << endl; swap(s1, s2); cout << s1.str() << endl; cout << s2.str() << endl; } void test_string10() { string url1("https://legacy.cplusplus.com/reference/string/string/substr/"); string url2("http://www.baidu.com/s?ie=utf-8&f=8&rsv_bp=1&rsv_idx=1&tn=65081411_1_oem_dg&wd=%E5%90%8E%E7%BC%80%20%E8%8B%B1%E6%96%87&fenlei=256&rsv_pq=0xc17a6c03003ede72&rsv_t=7f6eqaxivkivsW9Zwc41K2mIRleeNXjmiMjOgoAC0UgwLzPyVm%2FtSOeppDv%2F&rqlang=en&rsv_dl=ib&rsv_enter=1&rsv_sug3=4&rsv_sug1=3&rsv_sug7=100&rsv_sug2=0&rsv_btype=i&inputT=1588&rsv_sug4=6786"); string protocol, domain, uri; size_t i1 = url1.find(':'); if (i1 != string::npos) { protocol = url1.substr(0, i1 - 0); cout << protocol.str() << endl; } // strchar size_t i2 = url1.find('/', i1 + 3); if (i2 != string::npos) { domain = url1.substr(i1 + 3, i2 - (i1 + 3)); cout << domain.str() << endl; uri = url1.substr(i2 + 1); //cout << uri.str() << endl; } // strstr size_t i3 = url1.find("baidu"); cout << i3 << endl; } void test_string11() { string s1; getline(cin, s1); //cin >> s1; cout << s1; } }
test测试代码
#define _CRT_SECURE_NO_WARNINGS 1 #include"String.h" int main() { ljp::test_string1(); ljp::test_string2(); ljp::test_string3(); ljp::test_string4(); ljp::test_string5(); ljp::test_string6(); ljp::test_string7(); ljp::test_string8(); ljp::test_string9(); ljp::test_string10(); ljp::test_string11(); return 0; }
