[英]Getting errors trying to implement an operator<<?
我是c ++的新手,仍然尝试通过构造函数等来掌握类的实现。
我有一个程序,该程序分为3个文件:标头文件,类实现文件和驱动程序文件。
在头文件中,我收到一条错误消息“此行代码的朋友运算符<<(ostream&,ARRAY&);缺少显式类型(假定为'int');
在我的类实现文件中,我收到此朋友函数的错误,说我无权访问私有成员。
在我的驱动程序文件中,此代码出现错误“无法确定哪个实例重载了功能'endl'”:cout <
我将在下面留下一些代码,首先是.h文件,然后是类实现文件,然后是驱动程序文件。 非常感谢您为清除此问题提供的任何帮助。
头
#include <iostream>
#include <string>
#include <fstream>
using namespace std;
class ARRAY
{
public:
ARRAY();
ARRAY(int );
ARRAY(const ARRAY &);
~ARRAY();
friend operator<<(ostream &, ARRAY &);
private:
string *DB;
int count;
int capacity;
};
实施文件
#include "array.h"
ARRAY::ARRAY()
{
cout<<"Default Constructor has been called\n";
count = 0;
capacity = 2;
DB = new string[capacity];
}
ARRAY::ARRAY(int no_of_cells)
{
cout<<"Explicit-Value Constructor has been called\n";
count = 0;
capacity = no_of_cells;
DB = new string[capacity];
}
ARRAY::ARRAY(const ARRAY & Original)
{
cout<<"The copy constructor has been invoked\n";
count = Original.count;
capacity = Original.capacity;
DB = new string[capacity];
for(int i=0; i<count; i++)
{
DB[i] =Original.DB[i];
}
}
inline ARRAY::~ARRAY()
{
cout<<"Destructor Called\n";
delete [ ] DB;
}
ostream & operator<<(ostream & out, ARRAY & Original)
{
for(int i=0; i< Original.count; i++)
{
out<<"DB[" << i <<"] = "<< Original.DB[i]<<endl;
}
return out;
}
驱动档案
#include <iostream>
#include <string>
#include "array.h"
using namespace std;
int main()
{
cout<<"invoking the default constructor (11)"<<endl;
ARRAY myArray;
cout<<"Output after default constructor called\n";
cout<<myArray<<endl<<endl;
cout<<"invoking the explicit-value constructor (12)"<<endl;
ARRAY yourArray(5);
cout<<"Output after explicit-value constructor called\n";
//cout<<yourArray<<endl<<endl;
cout<<"invoking the copy constructor (3)"<<endl;
ARRAY ourArray = myArray;
cout<<"Output after copyconstructor called\n";
cout<<ourArray<<endl<<endl;
return 0;
}
您放弃了返回类型:
friend ostream& operator<<(ostream &, ARRAY &);
正如卡尔·诺鲁姆(Carl Norum)在解决方案中提到的
You left off the return type:
friend ostream& operator<<(ostream &, ARRAY &);
你也有删除inline
inline ARRAY::~ARRAY()
{
cout<<"Destructor Called\n";
delete [ ] DB;
}
成为
ARRAY::~ARRAY()
{
cout<<"Destructor Called\n";
delete [ ] DB;
}
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