运行下这个，看看怎么回事 - C++

鈊賥wo埋單

电梯直达

1^#

发表于 2009-11-3 03:31:03 | 只看该作者回帖奖励

|倒序浏览 |阅读模式

今天在两台机子上面运行结果一个报错另外一个没报错一个是VC++6.0的英文版没报错中问版的报错了郁闷怎么回事
#include <iostream>
using namespace std;
class String
{
public:
String() { inside= new char(50);}//ok
String(char *get)
{for(int i=0;i<strlen(get);i++)
inside[i]=get[i];}
String(String& s1)
{
inside=new char (s1.length());
inside=s1.inside;
}//ok
int find(String& s2);
int length();//ok
~String () {}
void operator =(String& c1);//ok
String operator +(String& c2);//ok
friend istream& operator >>(istream &cin,String &o1);//ok
friend ostream& operator <<(ostream &cout,String &o2);//ok
bool operator > (String c3);
bool operator < (String c4);
char operator [](int x);//ok
private:
char *inside;
};
int String::find(String& s2)
{
if(s2.length()>length())
return -1;
else
{
int t=0,i=0;
for(;i<length(),t<s2.length();i++)
if(inside[i]==s2.inside[t])
t++;
if(t==s2.length())
return i-t;
else
return -1;
}
}
int String::length()
{
int len(0);
for(int i=0;inside[i]!='\0';i++,len++)
;
return len;
}
void String::operator =(String& c1)
{
inside=c1.inside;
}
String String::operator +(String& c2)
{
int t=length();
for(int nu=0;nu<c2.length()+1;nu++)
inside[nu+t]=c2.inside[nu];
return *this;
}
istream& operator >>(istream& cin,String& o1)
{
cin>>o1.inside;
return cin;
}
ostream& operator <<(ostream& cout,String& o2)
{
cout<<o2.inside;
return cout;
}
bool String::operator >(String c3)
{
if(strcmp(inside,c3.inside)==1)
return true;
else
return false;
}
bool String::operator <(String c4)
{
if(strcmp(inside,c4.inside)==-1)
return true;
else
return false;
}
char String::operator [](int x)
{
return *(inside+x);
}
int main()
{
String s1,s2,s3;
cin>>s1>>s2;
s3=s1+s2;
cout<<s3<<endl;
for(int i=0;i<s3.length();i++)
cout<<s3[i];
cout<<endl;
if(s1>s2)
cout<<s1<<" is more lager than "<<s2<<endl;
//cout<<s3.find(s2);
return 0;
}

收藏0

使用道具举报

落叶秋雨

2^#

发表于 2009-11-3 03:31:05 | 只看该作者

我这运行没问题，但song4说他编译有问题，根据song4那边编译出错信息看是友元不能访问私有成员的问题，VC的报错类似于：
error C2248: 'inside' : cannot access private member declared in class 'String'

如果你也是这个问题的话那么就不是因为中文和英文VC的区别，而是vc6的bug，你把sp6 for vc6.0的补丁装上应该没事了

最后，申明一下，如果你的编译器编译代码出了问题，你想要别人帮你解答的话应该把你看到的出错信息贴出来，否则别人不好下手帮你解决，因为问题都不知道是什么

回复支持反对

使用道具举报

轌婲の滿天飛

3^#

发表于 2009-11-3 03:31:06 | 只看该作者

看了半天，郁闷半天
是个八哥．．．．
郁闷
还好问了aogun怎么回事，要不我就疯了

回复支持反对

使用道具举报

乄獨萊◇獨徍

4^#

发表于 2009-11-3 03:31:07 | 只看该作者

谢谢两位
下次我会注意的

回复支持反对

使用道具举报

阳光aiq浪子

5^#

发表于 2009-11-3 03:31:08 | 只看该作者

s3=s1+s2; //line 95 here is error, no match for 'operator='

回复支持反对

使用道具举报

══════

6^#

发表于 2009-11-3 03:31:09 | 只看该作者

以下是引用kai在2006-6-30 9:53:50的发言：

s3=s1+s2; //line 95 here is error, no match for 'operator='
代码中已经重载了

void operator =(String& c1);//ok
String operator +(String& c2);//ok
friend istream& operator >>(istream &cin,String &o1);//ok
friend ostream& operator <<(ostream &cout,String &o2);//ok

回复支持反对

使用道具举报

爱随缘

7^#

发表于 2009-11-3 03:31:10 | 只看该作者

it is depend on which compiler you uesed. When you use gcc, you will get error.
strictly speaking, you should define your copy constructor and assignment function in this form

Classname(const Classname & object); // copy constructor
// pay attention to "const", you should not forget this keyword

Classname & operator=(const Classname & object); // assignment
// pay attention to "const", you should not forget this keyword

I have his class rewritten, take a look.

程序代码:

#include <iostream>
using namespace std;

class String
{
public:
String()
{
inside= new char[50];
inside[49] = '\0';
}
String(const char * get)
{
int length = strlen(get);
inside = new char[length + 1];
strcpy(inside, get);
inside[length] = '\0';
}
String(const String & s1) // this is a copy constructor,
// it must defined it with using keyword "const",
// when you write your code strictly.
// with keyword const to
// tell your compiler,
// this parameter will be just used but not changed.
{
int size = strlen(s1.inside) + 1;
inside = new char[size];
strcpy(inside, s1.inside);
inside[size-1] = '\0';
}//ok
int find(String & s2);
int length();//ok

~String ()
{
if(inside)
delete [] inside;
}
String & operator=(const String & c1);//ok
String & operator +(const String & c2);//ok
friend istream& operator >>(istream &cin,String &o1);//ok
friend ostream& operator <<(ostream &cout,String &o2);//ok

bool operator > (String c3);
bool operator < (String c4);
char operator [](int x);//ok
private:
char *inside;
};

int String::find(String & s2)
{
if(s2.length()>length())
return -1;
else
{
int t=0,i=0;
for(;i<length(),t<s2.length();i++)
if(inside[i]==s2.inside[t])
t++;
if(t==s2.length())
return i-t;
else
return -1;
}
}

int String::length()
{
return strlen(inside);
}

String & String::operator=(const String & c1)
{
if((strcmp(inside, c1.inside) == 0) && inside == c1.inside)
return *this;

int size = strlen(c1.inside) + 1;
inside = new char[size];
strcpy(inside, c1.inside);
inside[size - 1] = '\0';
return *this;
}

String & String::operator +(const String & c2)
{
int size = length() + strlen(c2.inside) + 1;
char * temp = new char[size];
strcpy(temp, inside);
strcat(temp, c2.inside);
inside = temp;

return *this;
}

istream& operator >>(istream& cin,String& o1)
{
cin>>o1.inside;
return cin;
}

ostream& operator <<(ostream& cout,String& o2)
{
cout<<o2.inside;
return cout;
}

bool String::operator >(String c3)
{
if(strcmp(inside,c3.inside)==1)
return true;
else
return false;
}
bool String::operator <(String c4)
{
if(strcmp(inside,c4.inside)==-1)
return true;
else
return false;
}
char String::operator [](int x)
{
return *(inside+x);
}

int main()
{
char c[] = "hello 000 world";
char c1[] = "wor";
String s1(c);
String s2(c1);
String s3 = s1 + s2;

cout<<s3<<endl;
for(int i=0;i<s3.length();i++)
cout<<s3[i];
cout<<endl;
if(s1>s2)
cout<<s1<<" is more lager than "<<s2<<endl;
cout<<s3.find(s2);
return 0;
}

回复支持反对

使用道具举报

﹎想埝祢⿰

8^#

发表于 2009-11-3 03:31:13 | 只看该作者

谢谢kai的讲解
可是我还是有点不明白
你在上面的构造函数里面
String(const String & s1) // this is a copy constructor,
// it must defined it with using keyword "const",
// when you write your code strictly.
// with keyword const to
// tell your compiler,
// this parameter will be just used but not changed.
上面的红色部分我不明白
就算我没告诉它这个是CONST的
只要下面没有错误的使用应该也不会出错才对
我用的是VC++6.0

回复支持反对

使用道具举报

释放压力

9^#

发表于 2009-11-3 03:31:14 | 只看该作者

you should know the meaning of const and you should know what is standard in C/C++

回复支持反对

使用道具举报

→莲佳

10^#

发表于 2009-11-3 03:31:16 | 只看该作者

谢谢kai

回复支持反对

使用道具举报

		自动登录	找回密码
密码			注册