c++9月23日

1.My_string

头文件

#ifndef MY_STRINGHEAD_H
#define MY_STRINGHEAD_H#include <iostream>
#include <cstring>
using namespace std;class My_string
{
private:char *ptr;//指向字符数组的指针int size;//字符数组的最大容量int len ;//当前字符串的长度
public:My_string(){this->size=15;this->len=0;this->ptr[len]='\0';}My_string(const char *src);//有参构造My_string(const My_string & other);//拷贝构造My_string & operator=(const My_string &other);~My_string();//析构函数bool My_empty();//判空void push_back(char value);//尾插void pop_back();//尾删char * data ();char &at(int index);int get_len();int get_size();void Double_String();//双倍扩容void show();
};#endif // MY_STRINGHEAD_H

功能函数

#include "my_stringhead.h"My_string::My_string(const char *src)//有参构造{this->size = strlen(src);this->len=this->size;this->ptr = new char[this->size+1];strcpy(ptr,src);}My_string::My_string(const My_string & other):size(other.size),len(other.len)//拷贝构造{this->ptr = new char[this->size+1];strcpy(this->ptr,other.ptr);}My_string & My_string::operator=(const My_string &other)//拷贝赋值{if(this!=&other){this->size = other.size;this->len = other.len;strcpy(this->ptr,other.ptr);}return *this;}My_string::~My_string()//析构函数{delete this->ptr;}bool My_string:: My_empty()//判空{return len==0;}void My_string:: push_back(char value)//尾插{this->size++;char *Newptr=new char[this->size];strcpy(Newptr,ptr);delete this->ptr;this->ptr=Newptr;this->ptr[this->len]=value;this->len++;this->ptr[this->len]='\0';}void My_string::pop_back()//尾删{this->size--;this->len--;this->ptr[this->len]='\0';}char & My_string::at(int index){if(index>=0&&index<this->len){return this->ptr[index];}else{cout<<"输入不合法"<<endl;exit(-1);}}char *My_string::data ()//转换为c风格字符串{return this->ptr;}int  My_string::get_len(){return this->len;}int My_string:: get_size(){return this->len;}void My_string::Double_String()//双倍扩容{if(this->len+1>=this->size){this->size*=2;char *Newptr=new char[this->size];strcpy(Newptr,ptr);delete this->ptr;this->ptr=Newptr;}}void My_string:: show(){cout<<this->ptr<<endl;}

主函数

#include "my_stringhead.h"int main()
{My_string str("hello world");str.show();My_string str1;str1.operator = (str);str1.show();return 0;
}

2.思维导图