cpp
复制代码
#include <iostream>
#include <cstring>
using namespace std;
class myString
{
private:
char *str;
int size;
public:
//无参构造
myString():size(10)
{
str = new char[size]; //构造出一个长度为10的字符串
strcpy(str,""); //赋值为空串
}
//有参构造
myString(const char *s)
{
size = strlen(s);
str = new char[size+1];
strcpy(str,s);
}
//拷贝构造
myString(const myString &other):size(other.size)
{
str = new char [size];
strcpy(this->str,other.str);
cout<<"拷贝构造函数"<<endl;
}
//析构函数
~myString()
{
delete[] this->str;
cout<<"析构函数"<<endl;
}
//拷贝赋值函数
myString &operator = (const myString &other)
{
size = other.size;
strcpy(str,other.str);
cout<<"拷贝赋值函数"<<endl;
return *this;
}
//判空函数
bool str_empty(const char *str) const
{
if(str ==NULL||*str=='\0')
{
return true;
}
else
return false;
}
//size函数
int str_size(const char *str)const
{
return sizeof(str);
}
//c_str函数
const char *c_str() const
{
return str;
}
//at函数
char &at(int pos)
{
return str[pos];
}
//成员函数版实现加号运算符重载
myString operator+(const myString &R)const
{
myString new_string = *this;
delete[] new_string.str;
int len =strlen(this->str)+strlen(R.str)+1;
new_string.str = new char[len];
strcpy(new_string.str,this->str);
strcat(new_string.str,R.str);
return new_string;
}
//成员函数版实现加等于运算符重载
myString &operator+=(const myString &R)
{
int len = strlen(str)+strlen(R.str)+1;
char *s =this->str;
str = nullptr;
delete [] str;
str = new char [len];
strcpy(this->str,s);
strcat(this->str,R.str);
return *this;
}
//关系运算符重载
bool operator>(const myString &R)const
{
//先求出长度
int len1 = strlen(this->str);
int len2 = strlen(R.str);
int minlen =(len1<len2?len1:len2);
for(int i=0;i<minlen;i++)
{
if(this->str[i]>R.str[i])
{
return true;
}
else if(this->str[i]<R.str[i])
{
return false;
}
}
return len1>len2;
}
//成员函数版实现中括号运算符重载
char & operator[](int index)
{
if(index>=0&&index<size)
{
return str[index];
}
}
//展示函数
void show()
{
cout<<"str = "<<str<<" size = "<<size<<endl;
}
};
int main()
{
myString s1("hello");
s1[0]='H';
s1.show();
myString s2("world");
s2.show();
myString s6 =s1;
s6.show();
myString s3;
s3 = s1 + s2;
cout<<s3.c_str()<<endl;
myString s4("hahaha");
s4+=s1;
cout<<s4.c_str()<<endl;
if(s3>s2)
{
cout<<"yes"<<endl;
}
else
cout<<"no"<<endl;
myString s5("daydayup");
s5.show();
return 0;
}