2024-05-02 08:57:25
我还加了一个>>重载
#include<iostream>
#include<string>
using namespace std;
/*每个成员函数都是只归对象使用的,当一个对象调用成员时,这里面的成员只归该对象所有,只有该对象可以修改*/
class String
{
public:
String();
String(char *ch);
/*复制构造函数在用 该对象的一个对象初始化另一个对象的时候 需要调用复制构造函数*/
String(const String &); //复制构造函数
~String(){ cout << "正在执行析构函数!" << endl; }
friend ostream &operator << (ostream &out, String &a)
{
out << a.p;
return out;
}
friend istream &operator >> (istream &in, String &a)
{
in >> a.p;
return in;
}
private:
String(unsigned short int length);
int len;
char *p;
};
String::String()
{
cout << "调用默认构造函数!" << endl;
len = 0;
p = new char;
*p = '\0';
}
String::String(char *ch)
{
cout << "正在执行带一个参数*ch的构造函数" << endl;
len = strlen(ch);
p = new char[len + 1];
for (int i = 0; i < len; i++)
{
p[i] = ch[i];
}
p[len] = '\0';
}
String::String(unsigned short int length)
{
cout << "正在执行带一个参数unsigned short int 的构造函数" << endl;
len = length;
p = new char[length + 1]; //这里的p是对象str的成员
for (int i = 0; i <= length; i++)
p[i] = '\0';
}
int main()
{
String str("美好世界!");
cout << str << endl;
return 0;
}