返回引用

参考：https://www.cnblogs.com/codingmengmeng/p/5871254.html

 

#define  _CRT_SECURE_NO_WARNINGS
#include <iostream>
using namespace std;
class String
{
private:
	char *str;
	int len;
public:
	String(const char* s);//构造函数的申明
	String operator=(const String& another);
	void show()
	{
		cout << "value =" << str << endl;
	}
	String(const String& another)
	{
		len = another.len;
		str = new char[len + 1];
		strcpy(str, another.str);
		cout << "拷贝构造函数" << endl;
	}
	~String()
	{
		delete[] str;
		cout << "析构函数" << endl;
	}
};
String::String(const char*s)
{
	cout << "构造函数" << endl;
	len = strlen(s);
	str = new char[len + 1];
	strcpy(str, s);
}
String String::operator=(const String &another)
{
	if (this==&another)
	{
		return *this;
	}
	delete[] str;
	len = another.len;
	str = new char[len + 1];
	strcpy(str,another.str);
	return *this;
}
int main()
{
	String str1("china");
	String str2("tianjin");
	String str3("wuhu");
	str1.show();
	str2.show();
	str3.show();
	(str3 = str1) = str2;//str3.operator=(str1.operator=(str2))    
	str3.show();
	str1.show();
	return 0;

}