String类的简易实现，用到了构造函数、析构函数、重载运算符、拷贝构造函数、友元函数等知识

String类的简易实现，用到了构造函数、析构函数、重载运算符、拷贝构造函数、友元函数等知识

参考资料：《高质量C++C编程指南》

运行平台：VS2008

Cpp代码







#include<iostream>
using namespace std;

class String
{
public:
String(const char *str = NULL);

String(const String &other);

~String(void);
String & operator=(const String &other);

bool operator==(const String &str);

friend ostream & operator<<(ostream& o,const String &str);

private:
char *m_data;
};

/*
构造、析构、拷贝构造、赋值运、流输出运算
*/

String::String(const char *str)

{
if (str == NULL){
m_data = new char[1];

*m_data='\0';
}else{
int len=strlen(str);

m_data = new char[len+1];

strcpy(m_data,str);
}
}
String::~String(void)
{
delete [] m_data;
}

String::String(const String &other)

{
int len = strlen(other.m_data);

m_data = new char[len+1];

strcpy(m_data,other.m_data);
}

String & String::operator=(const String &other)

{
if (this == &other)

return *this;

delete []m_data;

int len = strlen(other.m_data);

m_data = new char[len+1];

strcpy(m_data,other.m_data);

return *this;

}

bool String::operator==(const String &str)

{
return strcmp(m_data,str.m_data) == 0;

}

ostream & operator<<(ostream &o,const String &str)

{
o<<str.m_data;
return o;

int main()
{
String s = "hello";
String s2 = s;
String ss = "hello";
cout<<"s = "<<s<<endl;
cout<<"s2 = "<<s2<<endl;

cout<<boolalpha<<(ss == s)<<endl;
}

转自：/article/4244273.html