主函数
#include"head.h"
int main()
{My_string s2("hello");My_string s3(5,'A');s2.show();s3.show();My_string s1=s2;s1.show();My_string s4;s4=s3;s4.show();if(s4.empty_if()){cout<<"该字符数组为空"<<endl;}else{cout<<"该字符数组不为空"<<endl;}s1.push_back('!');s1.show();s1.pop_back();s1.show();cout << "第一个位置是 : " << s1.at(1) << endl;s1.clear();s1.show();cout << "s2当前的长度是 : " << s2.get_length()<<"s3当前的最大容量是"<<s3.get_size()<<endl;return 0;
}
头文件：
#ifndef HEAD_H
#define HEAD_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; //字符串的最大容量int len; //字符串的当前容量
public:My_string();My_string(const char *src);My_string(int num,char value);My_string(const My_string &other);My_string &operator=(const My_string &other);void show();bool empty_if();void push_back(char value);void pop_back();char &at(int index);void clear();int get_length();int get_size();~My_string();
};
#endif // HEAD_H
源文件：
#include"head.h"
using namespace std;My_string::My_string():size(15)
{this->ptr =new char[size];this->ptr [0]='\0';this->len=0;
}
My_string::My_string(const char *src)
{this->len=strlen(src);this->size=this->len+1;this->ptr =new char[size];strcpy(this->ptr,src);
}
My_string::My_string(int num,char value)
{this->len=num;this->size=this->len+1;this->ptr =new char[num];for(int i=0;i<5;i++){this->ptr[i]=value;}
}
My_string::My_string(const My_string &other)
{this->len = other.len;this->size = other.size;this->ptr = new char[size]; // 分配新的内存strcpy(this->ptr, other.ptr); // 复制源对象的字符串内容
}
My_string&My_string ::operator=(const My_string &other)
{if(this != &other) //防止自己给自己赋值{this->size = other.size;this->len = other.len;this->ptr = new char[size];strcpy(this->ptr ,other.ptr); //深拷贝}return *this; //返回值自身的引用
}
void My_string::show()
{cout<<this->ptr<<endl;
}
My_string::~My_string()
{delete this->ptr;
}bool My_string::empty_if()
{return this->len==0;
}
void My_string::push_back(char value){ptr[len] = value; // 在尾部添加字符ptr[len+1] = '\0'; // 确保字符串以空字符结尾this->len++;}void My_string::pop_back(){if (this->len > 0) // 确保字符串非空{ptr[len-1] = '\0'; // 更新终止符this->len--;}}char &My_string::at(int index){return ptr[index-1]; // 返回引用以支持修改}void My_string::clear(){this->len = 0; // 重置长度为 0ptr[0] = '\0'; // 以空字符结束}int My_string::get_length(){return this->len;}int My_string::get_size(){return this->size;} 
