STL-String类

/**********************************mystring.h*************************************/

#pragma once#define  _CRT_SECURE_NO_WARNINGS#include<iostream>#include<cstring>using namespace std;/*代码除创建的临时buf外,其他全部为深拷贝*/class mystring{public:friend ostream & operator <<(ostream &,const  mystring & myTT); //重载输出流friend istream & operator >>(istream &, mystring & MyTT);  //重载输入流public:mystring();mystring(char *p); mystring(const mystring & str2); //重写，避免浅拷贝~mystring();public:mystring & operator=(char *p); //重载=  实现 str1="asdas";  //str1为对象,下面同义mystring & operator=(const mystring & mystr);  //重写= 实现 str1=str2 深拷贝mystring & operator+=(const mystring& mystr);  //重载+= 实现 str1+=str2;mystring & operator+=(char *p);  //重载+= 实现 str1+="sdas";static int mystrcmp(const mystring *str1, const mystring *str2); //比较两对象，相同返回0,否则: 若str1.size>str2.size 返回1，反之返回-1， //长度相等，判断第一个不同的字母char &operator [](int n);  //重载[] 便于输出public:char * srea(char *p);  //查找，存在返回出现首字符地址，不存在返回nullptrvoid Insert(char *p, char *key); //插入，默认为p后面插入void Append(char *key);  //尾部插入void StartInsert(char *key); //头部插入void del(char *p);  //删除 首个出现的pvoid delAll(char *p);  //删除所有的 pvoid exchang(char *p, char *key); //替换  将首个出现的p替换为keyvoid exchangAll(char *p, char *key); //替换所有的 pint _size();  //返回字符串sizeprivate:int size;  //字符串的长度char *pstr;  //字符串源};

/**************************************************************************************************/

/*************************************************************************************************/

/************************************mystring.cpp*************************************************/

#include "mystring.h"ostream& operator <<(ostream &, const mystring & myTT)  //友元重载输出{<span style="white-space:pre"></span>return cout << myTT.pstr;}istream & operator >>(istream & is, mystring & MyTT)  //友元重载输入{<span style="white-space:pre"></span>is>>MyTT.pstr;   //pstr<span style="white-space:pre"></span>MyTT.size = strlen(MyTT.pstr);<span style="white-space:pre"></span>char *tmp = new char[MyTT.size + 1];<span style="white-space:pre"></span>strcpy(tmp, MyTT.pstr);  //需重新拷贝进来，原MyTT.pstr并没有分配内存<span style="white-space:pre"></span>MyTT.pstr = tmp;<span style="white-space:pre"></span>return is;}mystring::mystring() //构造 0{<span style="white-space:pre"></span>this->size = 1;<span style="white-space:pre"></span>this->pstr = new char[1];<span style="white-space:pre"></span>*(this->pstr) = '\0';}mystring::mystring(char *p)  //构造1{<span style="white-space:pre"></span>this->size = strlen(p);<span style="white-space:pre"></span>this->pstr = new char[this->size + 1];<span style="white-space:pre"></span>memset(this->pstr, 0, this->size + 1);<span style="white-space:pre"></span>strcpy(this->pstr, p);}mystring::mystring(const mystring & str2)  //构造2{<span style="white-space:pre"></span>this->size = str2.size;<span style="white-space:pre"></span>char *tmp = new char[this->size + 1];<span style="white-space:pre"></span>memset(tmp, 0, this->size + 1);<span style="white-space:pre"></span>strcpy(tmp, str2.pstr);<span style="white-space:pre"></span>free(this->pstr);<span style="white-space:pre"></span>this->pstr = tmp;}mystring::~mystring() //析构{<span style="white-space:pre"></span>free(this->pstr);<span style="white-space:pre"></span>this->pstr = nullptr;}int mystring::_size(){<span style="white-space:pre"></span>return this->size;}char * mystring::srea(char *p)  //查找字符串 ,返回字符串所在位置首指针{<span style="white-space:pre"></span>int plen = strlen(p);<span style="white-space:pre"></span>int i = 0;<span style="white-space:pre"></span>while (i < this->size)<span style="white-space:pre"></span>{<span style="white-space:pre"></span>if (this->pstr[i] == *p)<span style="white-space:pre"></span>{<span style="white-space:pre"></span>int j = 0;<span style="white-space:pre"></span>int flag = 1;<span style="white-space:pre"></span>for (; j < plen; j++)<span style="white-space:pre"></span>{<span style="white-space:pre"></span>if (this->pstr[i + j] != p[j])<span style="white-space:pre"></span>{<span style="white-space:pre"></span>flag = 0;<span style="white-space:pre"></span>break;<span style="white-space:pre"></span>}<span style="white-space:pre"></span>}<span style="white-space:pre"></span>if (flag)<span style="white-space:pre"></span>{<span style="white-space:pre"></span>return this->pstr + i;<span style="white-space:pre"></span>}<span style="white-space:pre"></span>}<span style="white-space:pre"></span>i++;<span style="white-space:pre"></span>}<span style="white-space:pre"></span>return nullptr;}void mystring::Insert(char *p, char *key)//key 要插入的字符串  p插入的位置字符串后面{<span style="white-space:pre"></span>char *tmp = this->srea(p);<span style="white-space:pre"></span>if (tmp != nullptr)<span style="white-space:pre"></span>{<span style="white-space:pre"></span>char * buf = new char[this->size + strlen(key) + 1];<span style="white-space:pre"></span>memset(buf, 0, this->size + strlen(key) + 1); //重新分配内存并初始化<span style="white-space:pre"></span>char cc = *(tmp + strlen(p));<span style="white-space:pre"></span>*(tmp + strlen(p)) = '\0'; //方便拷贝第一段<span style="white-space:pre"></span>strcpy(buf, this->pstr);<span style="white-space:pre"></span>strcpy(buf + (tmp - this->pstr) + strlen(p), key); //插入<span style="white-space:pre"></span>*(tmp + strlen(p) + 1) = cc;<span style="white-space:pre"></span>strcpy(buf + (tmp - this->pstr) + strlen(p) + strlen(key), tmp + strlen(p) + 1);  //拷贝后面的内容<span style="white-space:pre"></span>free(this->pstr);<span style="white-space:pre"></span>this->pstr = buf;<span style="white-space:pre"></span>this->size = this->size + strlen(key);<span style="white-space:pre"></span>}<span style="white-space:pre"></span>else<span style="white-space:pre"></span>{<span style="white-space:pre"></span>cout << "Can't find this string" << endl;<span style="white-space:pre"></span>}}void mystring::Append(char *key)  //尾部插入{<span style="white-space:pre"></span>char *tmp = new char[this->size + strlen(key) + 1];<span style="white-space:pre"></span>memset(tmp, 0, this->size + strlen(key) + 1);<span style="white-space:pre"></span>strcpy(tmp, this->pstr);<span style="white-space:pre"></span>strcpy(tmp + this->size, key);<span style="white-space:pre"></span>free(this->pstr);<span style="white-space:pre"></span>this->pstr = tmp;<span style="white-space:pre"></span>this->size = this->size + strlen(key);}void mystring::StartInsert(char *key) //头部插入{<span style="white-space:pre"></span>char *tmp = new char[this->size + strlen(key) + 1];<span style="white-space:pre"></span>memset(tmp, 0, this->size + strlen(key) + 1);<span style="white-space:pre"></span>strcpy(tmp, key);<span style="white-space:pre"></span>strcpy(tmp + strlen(key), this->pstr);<span style="white-space:pre"></span>free(this->pstr);<span style="white-space:pre"></span>this->pstr = tmp;<span style="white-space:pre"></span>this->size = this->size + strlen(key);}void mystring::del(char *p) //删除首个出现的p字符串{<span style="white-space:pre"></span>char *tmp = this->srea(p);<span style="white-space:pre"></span>if (tmp != nullptr)<span style="white-space:pre"></span>{<span style="white-space:pre"></span>char *ptmp = new char[this->size - strlen(p) + 1];<span style="white-space:pre"></span>memset(ptmp, 0, this->size - strlen(p) + 1);  //重新开辟内存<span style="white-space:pre"></span>*tmp = '\0';<span style="white-space:pre"></span>strcpy(ptmp, this->pstr); //拷贝<span style="white-space:pre"></span>strcpy(ptmp + (tmp - this->pstr), tmp + strlen(p)); //拷贝字符串后面的部分<span style="white-space:pre"></span>free(this->pstr); //释放原字符串池<span style="white-space:pre"></span>this->pstr = ptmp;<span style="white-space:pre"></span>this->size -= strlen(p);  //刷新对象属性<span style="white-space:pre"></span>}<span style="white-space:pre"></span>else<span style="white-space:pre"></span>{<span style="white-space:pre"></span>cout << "Can't find this string" << endl;<span style="white-space:pre"></span>}}void mystring::exchang(char *p, char *key)  //替换首个出现的 p字符串{<span style="white-space:pre"></span>char *tmp = this->srea(p);<span style="white-space:pre"></span>if (tmp != nullptr)<span style="white-space:pre"></span>{<span style="white-space:pre"></span>char *ptmp = new char[this->size + strlen(key) + 1];<span style="white-space:pre"></span>memset(ptmp, 0, this->size + strlen(key) + 1);<span style="white-space:pre"></span>*tmp = '\0';<span style="white-space:pre"></span>strcpy(ptmp, this->pstr); //拷贝前面<span style="white-space:pre"></span>strcpy(ptmp + (tmp - this->pstr), key); //拷贝用于替换的key<span style="white-space:pre"></span>strcpy(ptmp + (tmp - this->pstr) + strlen(key), tmp + strlen(p)); //拷贝后面的字符串<span style="white-space:pre"></span>free(this->pstr);<span style="white-space:pre"></span>this->pstr = ptmp;<span style="white-space:pre"></span>this->size = this->size - strlen(p) + strlen(key); //释放并刷新<span style="white-space:pre"></span>}<span style="white-space:pre"></span>else<span style="white-space:pre"></span>{<span style="white-space:pre"></span>cout << "Can't find this string" << endl;<span style="white-space:pre"></span>}}void mystring::delAll(char *pkey){<span style="white-space:pre"></span>char *p = srea(pkey);<span style="white-space:pre"></span>if (p != nullptr)<span style="white-space:pre"></span>{<span style="white-space:pre"></span>del(pkey);<span style="white-space:pre"></span>delAll(pkey);  //递归调用<span style="white-space:pre"></span>}}void mystring::exchangAll(char *p, char *key){<span style="white-space:pre"></span>char *ptmp = srea(p);<span style="white-space:pre"></span>if (ptmp != nullptr)<span style="white-space:pre"></span>{<span style="white-space:pre"></span>exchang(p, key);<span style="white-space:pre"></span>exchangAll(p, key); //递归调用<span style="white-space:pre"></span>}}char & mystring::operator[](int n)  //重载[]{<span style="white-space:pre"></span>return this->pstr[n];}int mystring::mystrcmp(const mystring *str1, const mystring *str2)  //比较函数{<span style="white-space:pre"></span>if (str1->size > str2->size)<span style="white-space:pre"></span>{<span style="white-space:pre"></span>return 1;<span style="white-space:pre"></span>}<span style="white-space:pre"></span>else if (str1->size < str2->size)<span style="white-space:pre"></span>{<span style="white-space:pre"></span>return -1;<span style="white-space:pre"></span>}<span style="white-space:pre"></span>else<span style="white-space:pre"></span>{<span style="white-space:pre"></span>int flag = 0;<span style="white-space:pre"></span>int i = 0;<span style="white-space:pre"></span>while (i++ < str1->size)<span style="white-space:pre"></span>{<span style="white-space:pre"></span>if (str1->pstr[i] != str2->pstr[i])<span style="white-space:pre"></span>{<span style="white-space:pre"></span>if (str1->pstr[i] > str2->pstr[i])<span style="white-space:pre"></span>{<span style="white-space:pre"></span>return 1;<span style="white-space:pre"></span>}<span style="white-space:pre"></span>else<span style="white-space:pre"></span>{<span style="white-space:pre"></span>return -1;<span style="white-space:pre"></span>}<span style="white-space:pre"></span>}<span style="white-space:pre"></span>}<span style="white-space:pre"></span>return 0;<span style="white-space:pre"></span>}}mystring & mystring::operator+=(char *p){<span style="white-space:pre"></span>char *ptmp = new char[this->size + strlen(p) + 1];<span style="white-space:pre"></span>strcpy(ptmp, this->pstr);<span style="white-space:pre"></span>strcpy(ptmp + this->size, p);<span style="white-space:pre"></span>free(this->pstr);  //释放原指针<span style="white-space:pre"></span>this->pstr = ptmp;  //重新定义指向<span style="white-space:pre"></span>this->size += this->size + strlen(p); //修改原字符串的长度值<span style="white-space:pre"></span>return *this;}mystring & mystring::operator+=(const mystring& mystr)  //重载 +={<span style="white-space:pre"></span>char *ptmp = new char[this->size + mystr.size + 1];<span style="white-space:pre"></span>strcpy(ptmp, this->pstr);<span style="white-space:pre"></span>strcpy(ptmp + this->size, mystr.pstr);<span style="white-space:pre"></span>free(this->pstr);  //释放原指针<span style="white-space:pre"></span>this->pstr = ptmp;  //重新定义指向<span style="white-space:pre"></span>this->size += this->size + mystr.size; //修改原字符串的长度值<span style="white-space:pre"></span>return *this;}mystring & mystring::operator=(const mystring & mystr){<span style="white-space:pre"></span>if (this->size >= strlen(mystr.pstr)) //不用重新分配内存<span style="white-space:pre"></span>{<span style="white-space:pre"></span>memcpy(this->pstr, 0, this->size + 1);<span style="white-space:pre"></span>strcpy(this->pstr, mystr.pstr);<span style="white-space:pre"></span>this->size = mystr.size;<span style="white-space:pre"></span>}<span style="white-space:pre"></span>else //重新分配<span style="white-space:pre"></span>{<span style="white-space:pre"></span>char *tmp = new char[strlen(mystr.pstr) + 1];<span style="white-space:pre"></span>free(this->pstr);<span style="white-space:pre"></span>this->pstr = nullptr;<span style="white-space:pre"></span>strcpy(tmp, mystr.pstr);<span style="white-space:pre"></span>this->pstr = tmp;<span style="white-space:pre"></span>}<span style="white-space:pre"></span>return *this;}mystring & mystring::operator=(char *p){<span style="white-space:pre"></span>if (this->size >= strlen(p))  //同上<span style="white-space:pre"></span>{<span style="white-space:pre"></span>memcpy(this->pstr, 0, this->size + 1);<span style="white-space:pre"></span>strcpy(this->pstr, p);<span style="white-space:pre"></span>}<span style="white-space:pre"></span>else<span style="white-space:pre"></span>{<span style="white-space:pre"></span>char *tmp = new char[strlen(p) + 1];<span style="white-space:pre"></span>free(this->pstr);<span style="white-space:pre"></span>this->pstr = nullptr;<span style="white-space:pre"></span>strcpy(tmp, p);<span style="white-space:pre"></span>this->pstr = tmp;<span style="white-space:pre"></span>}<span style="white-space:pre"></span>return *this;}