拷贝构造函数与赋值构造函数

来源：互联网发布：telnet 端口号不通编辑：程序博客网时间：2024/05/17 22:54

#include<iostream>
#include<cstring>
using namespace std;

class String
{
private:
char *m_data;
public:
String(const char *str);
String(const String &other);
String & operator=(const String &other);
~String();
};

String::String(const char *str)
{
cout<<"自定义构造函数"<<endl;
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(const String &other)
{
cout<<"自定义复制构造函数"<<endl;
int len = strlen(other.m_data);
m_data = new char[len + 1];
strcpy(m_data,other.m_data);
}

String & String::operator=(const String &other)
{
cout<<"自定义赋值函数"<<endl;
if(this == &other)
  return *this;
else {
  delete [] m_data;
  int len = strlen(other.m_data);
  m_data = new char[len + 1];
  strcpy(m_data,other.m_data);
  return *this;
}
}

String::~String()
{
delete [] m_data;
}

int main()
{
cout << "a(\"abc\")" << endl;
String a("abc");

cout << "b(\"cde\")" << endl;
String b("cde");

cout << " d = a" << endl;
String d = a;

cout << "c(b)" << endl;
String c(b);

cout << "c = a" << endl;
c = a;
getchar();
return 0;
}

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