【疑惑】cout输出字符串却显示的是地址

[mcmay]

各位大侠，麻烦看看下面的代码为什么在应该现实字符串的时候却显示了地址。谢谢！

// dma.h  -- inheritance and dynamic memory allocation
#ifndef DMA_H_
#define DMA_H_
#include <iostream>


class dmaABC
{
private:
	char * label;
	int rating;
public:
	dmaABC(const char * l = "null", int r = 0);
	dmaABC(const dmaABC & dma);
	virtual ~dmaABC();
	dmaABC & operator=(const dmaABC & dma);
	virtual void viewDMA() const = 0;
};
//  Base Class Using DMA
class baseDMA: public dmaABC
{
public:
    baseDMA(const char * l = "null", int r = 0);
    baseDMA(const baseDMA & rs);
    virtual ~baseDMA();
    baseDMA & operator=(const baseDMA & d);
    //friend std::ostream & operator<<(std::ostream & os,
                                 // const baseDMA & rs);
    virtual void viewDMA() const;
};

// derived class without DMA
// no destructor needed
// uses implicit copy constructor
// uses implicit assignment operator
class lacksDMA : public dmaABC
{
private:
    enum { COL_LEN = 40};
    char color[COL_LEN];
public:
    lacksDMA(const char * c = "blank", const char * l = "null",
              int r = 0);
    lacksDMA(const char * c, const lacksDMA & dma);
    //friend std::ostream & operator<<(std::ostream & os,
                                 // const lacksDMA & rs);
    virtual void viewDMA() const;
};

// derived class with DMA
class hasDMA : public dmaABC
{
private:
    char * style;
public:
    hasDMA(const char * s = "none", const char * l = "null",
              int r = 0);
    hasDMA(const char * s, const hasDMA & dma);
    hasDMA(const hasDMA & hs);
    ~hasDMA();
    hasDMA & operator=(const hasDMA & rs);
    //friend std::ostream & operator<<(std::ostream & os,
                                  //const hasDMA & rs);
    virtual void viewDMA() const;
};

#endif

// dma.cpp --dma class methods

#include "dma.h"
#include <cstring>

// dmaABC
dmaABC::dmaABC(const char * l, int r)
{
    label = new char[std::strlen(l) + 1];
    std::strcpy(label, l);
    rating = r;
}

dmaABC::dmaABC(const dmaABC & dma)
{
    label = new char[std::strlen(dma.label) + 1];
    std::strcpy(label, dma.label);
    rating = dma.rating;
}

dmaABC::~dmaABC()
{
    delete [] label;
}

dmaABC & dmaABC::operator=(const dmaABC & dma)
{
    if (this == &dma)
        return *this;
    delete [] label;
    label = new char[std::strlen(dma.label) + 1];
    std::strcpy(label, dma.label);
    rating = dma.rating;
    return *this;
}

void dmaABC::viewDMA() const
{
	using std::cout;
	using std::endl;

	cout << "Label: " << label << endl;
	cout << "Rating: " << rating << endl;
}

// baseDMA methods
baseDMA::baseDMA(const char * l, int r): dmaABC(l, r)
{
}

baseDMA::baseDMA(const baseDMA & rs) : dmaABC(rs)
{
}

baseDMA::~baseDMA()
{
}

baseDMA & baseDMA::operator=(const baseDMA & rs)
{
	dmaABC::operator=(rs);
    return *this;
}

void baseDMA::viewDMA() const
{
	dmaABC::viewDMA();
}

// lacksDMA methods
lacksDMA::lacksDMA(const char * c, const char * l, int r)
    : dmaABC(l, r)
{
    std::strncpy(color, c, 39);
    color[39] = '\0';
}

lacksDMA::lacksDMA(const char * c, const lacksDMA & rs)
    : dmaABC(rs)
{
    std::strncpy(color, c, COL_LEN - 1);
    color[COL_LEN - 1] = '\0';
}

void lacksDMA::viewDMA() const
{
	dmaABC::viewDMA();
	std::cout << "Color: " << std::cout << color << std::endl;  // 这里有问题吗？
}

// hasDMA methods
hasDMA::hasDMA(const char * s, const char * l, int r)
         : dmaABC(l, r)
{
    style = new char[std::strlen(s) + 1];
    std::strcpy(style, s);
}

hasDMA::hasDMA(const char * s, const hasDMA & rs)
         : dmaABC(rs)
{
    style = new char[std::strlen(s) + 1];
    std::strcpy(style, s);
}

hasDMA::hasDMA(const hasDMA & hs)
         : dmaABC(hs)  // invoke base class copy constructor
{
    style = new char[std::strlen(hs.style) + 1];
    std::strcpy(style, hs.style);
}

hasDMA::~hasDMA()
{
    delete [] style;
}

hasDMA & hasDMA::operator=(const hasDMA & hs)
{
    if (this == &hs)
        return *this;
    dmaABC::operator=(hs);  // copy base portion
    delete [] style;         // prepare for new style
    style = new char[std::strlen(hs.style) + 1];
    std::strcpy(style, hs.style);
    return *this;
}

void hasDMA::viewDMA() const
{
	dmaABC::viewDMA();
	std::cout << "Style: " << std::cout << style << std::endl;  // 这里有问题吗？
}

// usebrass3.cpp -- polymorphic example
// compile with acctacb.cpp
#include <iostream>
#include <string>
#include "dma.h"
const int CLIENTS = 4;

int main()
{
   using std::cin;
   using std::cout;
   using std::endl;

   dmaABC * p_clients[CLIENTS];
	char temp[81];
	int r;
   char kind;

   for (int i = 0; i < CLIENTS; i++)
   {
       cout << "Enter the label: " << endl;
	cin.getline(temp, 81);
       cout << "Enter the rating: ";
       cin >> r;
       cout << "Enter 1 for baseDMA or "
            << "2 for lacksDMA "
            << "or 3 for hasDMA : ";
       while (cin >> kind && (kind != '1' && kind != '2' && kind != '3'))
           cout <<"Enter either 1 or 2 or 3: ";
         if(kind == '1')
          p_clients[i] = new baseDMA(temp, r);
       else if (kind == '2')
		{
			cout << "Enter the color: ";
			char c[81];
			cin.getline(c, 81);
           p_clients[i] = new lacksDMA(c, temp, r);
		}
       else
       {
	   char s[81];
           cout << "Enter the style:" << endl;
	   cin.getline(s, 81);
           p_clients[i] = new hasDMA(s, temp, r);
        }
        while (cin.get() != '\n')
            continue;
   }
   cout << endl;
   for (int i = 0; i < CLIENTS; i++)
   {
       p_clients[i]->viewDMA();
       cout << endl;
   }
              
   for (int i = 0; i < CLIENTS; i++)
   {
       delete p_clients[i];  // free memory
   }
   cout << "Done.\n";    
   cin.get();
   return 0; 
}

运行结果：

Enter the label:
Dusk
Enter the rating: 7
Enter 1 for baseDMA or 2 for lacksDMA or 3 for hasDMA : 2
Enter the color: green
Enter the label:
Dulu
Enter the rating: 5
Enter 1 for baseDMA or 2 for lacksDMA or 3 for hasDMA : 1
Enter the label:
Mars
Enter the rating: 6
Enter 1 for baseDMA or 2 for lacksDMA or 3 for hasDMA : 3
Enter the style:
tiled
Enter the label:
Yek
Enter the rating: 8
Enter 1 for baseDMA or 2 for lacksDMA or 3 for hasDMA : 1

Label: Dusk
Rating: 7
Color: 61E9C3E8

Label: Dulu
Rating: 5

Label: Mars
Rating: 6
Style: 61E9C3E8

Label: Yek
Rating: 8

Done.

[www_adintr_com]

你输出的地址是 std::cout 的地址： std::cout << "Color: " << std::cout << color << std::endl; // 这里有问题吗？ 改成 std::cout << "Color: " << color << std::endl; std::cout << "Style: " << std::cout << style << std::endl; // 这里有问题吗？ 改成 std::cout << "Style: " << style << std::endl; 另外，你的 color 和 style 的值本身是空的，所以没有输出 因为你的输入放在 c 里面的，而传进去的参数却是 temp

[mcmay]

引用 1 楼 adlay 的回复:

你输出的地址是 std::cout 的地址： std::cout << "Color: " << std::cout << color << std::endl; // 这里有问题吗？ 改成 std::cout << "Color: " << color << std::endl; std::cout << "Style: " << std::cout << style << std::endl; // 这里有问题吗？ 改成 std::cout << "Style: " << style << std::endl; 另外，你的 color 和 style 的值本身是空的，所以没有输出 因为你的输入放在 c 里面的，而传进去的参数却是 temp

谢谢adlay！那个关于cout的问题我更正了，但是你说的“另外”的问题我还没看出来，我通过c和s传给color和style的值应该传到了啊，怎么会是temp呢？麻烦解释一下，谢谢。