应该是要加上：

#include 
    

---------------------------------------------------

C++ Primer Plus 中的 Listing 5.19

// textin4.cpp -- reading chars with cin.get()#include 
    
       // 加上：#include 
     
      int main(void){    using namespace std;    int ch;                         // should be int, not char    int count = 0;    while ((ch = cin.get()) != EOF) // test for end-of-file    {        cout.put(char(ch));        ++count;    }    cout << endl << count << " characters read\n";    return 0; }
     
    

textin4.cpp: 在函数‘int main()’中:textin4.cpp:10:29: 错误： ‘EOF’在此作用域中尚未声明

/* Listing 5.19 * textin4.cpp -- reading chars with cin.get() */#include 
    
     #ifndef EOF#define EOF -1#endifint main (void){	using namespace std;	int ch; // should be int, not char	int count = 0;		while ((ch = cin.get()) != EOF) // test for end-of-file	{		cout.put(char(ch));		++count;	}	cout << endl << count << " characters read\n";	return 0;}