字符串的运算符重载

最新推荐文章于 2021-12-18 21:44:59 发布

原创最新推荐文章于 2021-12-18 21:44:59 发布 · 925 阅读

2 ·

CC 4.0 BY-SA版权

本文详细介绍了C++中自定义字符串类的实现方法，包括构造、赋值、连接、比较、输入输出等基本操作，并通过实例展示了如何使用此类进行字符串处理。

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#include <iostream.h>
#include <cstring>
#include<windows.h>
class String
{
public:
	String(){p=NULL;}
	String(const String &);
	String(char *str);
    ~String();
	String & operator=(const String &);
	String operator+(const String &);
	friend bool operator>(String &string1,String &string2);
	friend bool operator< (String &string1, String &string2);
	friend bool operator== (String &string1, String &string2);
	friend bool operator!= (String &string1, String &string2);
	friend ostream& operator << (ostream&,const String&);  
    friend istream& operator >> (istream&,String&);   
    void display();
private:
	char *p;
};
String::String(const String &s)
{
	if(s.p)
		p=new char[strlen(s.p)+1]; 
	else p=0;  
    strcpy(p,s.p);  
}  

String::String(char *str)
{
	p=str;
}
String::~String()
{
	if(p!=NULL)
		delete p;
	p=NULL;
}
String& String::operator=(const String &s)
{
	if(p) 
	{delete[]p; p=new char[strlen(s.p)+1];}
	else  
		p=new char[strlen(s.p)+1];
	strcpy(p,s.p);
	return *this;
}
String String::operator +(const String &s)
{
	String temp;
	if(temp.p!=NULL)
		delete[]temp.p;
	temp.p = new char[strlen(p)+strlen(s.p)+1];
	strcpy(temp.p,p);
	strcat(temp.p,s.p);
	return temp;
}
bool operator>(String &string1,String &string2)
{
	if(strcmp(string1.p,string2.p)>0)
		return true;
	else
		return false;
}
bool operator<(String &string1,String &string2)
{
	if(!operator>(string1,string2))
		return true;
	else
		return false;
}
bool operator==(String &string1,String &string2)
{
	if(strcmp(string1.p,string2.p)==0)
		return true;
	else
		return false;
}
bool operator !=(String &string1, String &string2)
{
	if(!(string1.p==string2.p))
		return true;
	else
		return false;
}
ostream& operator <<(ostream &output,const String &s)
{
	output<<s.p;
	return output;
}
istream& operator >>(istream &intput,String &s)
{
	char temp[100000] = {"",};
	intput>>temp;
	s.p=temp;
	return intput;
}
void String::display()
{
	cout<<p<<endl;
}
void compare(String &string1,String &string2)
{if(operator>(string1,string2)==1)
{ cout<<"string1>string2"<<endl;}
else
if(operator<(string1,string2)==1)
{
	cout<<"string1<string2"<<endl;
}
if(operator==(string1,string2)==1)
{
	cout<<"string1=string2<<endl";
}
if(operator==(string1,string2)!=1)
{
	cout<<"string1!=string2"<<endl;
}
}
int main()
{
	String string1("Hello"),string2("World");
	cout<<"输出string1:";
	string1.display();
	cout<<"输出string2:";
	string2.display();
	cout<<"比较string1和string2:";
	compare(string1,string2);
	String string4,string5,string6;
	cout<<"string1和string2连接后赋值给string4:"<<endl;
	string4=string1+string2;
	string4.display();
	cout<<"输入string5:";
	cin>>string5; 
	cout<<"输出string5:"<<endl;
	cout<<string5<<endl;
	cout<<"string1赋值给string6:"<<endl;
	string6=string1;
	string6.display();
	system("pause");
	return 0;
} <img src="https://img-blog.youkuaiyun.com/20150427224508666" alt="" />