#include<iostream>
#include<fstream>
#include<cstdlib>

const int SIZE=60;

int main()
{
using namespace std;
char filename[SIZE];
ifstream inFile;

cout<<"Enter name of data file:";
cin.getline(filename,SIZE);
inFile.open(filename);
if(!inFile.is_open())
{
cout<<"Could not open the file "<<filename<<endl;
cout<<"Program terminating.\n";

}

double value;
double sum=0.0;
int count=0;

inFile>>value;
while(inFile.good())
{
++count;
sum+=value;
inFile>>value;
}

if(inFile.eof())
cout<<"End of file reached.\n";
else if(inFile.fail())
cout<<"Input terminated by data mimatch.\n";
else
cout<<"Input terminated for unknow reasons.\n";
if(count==0)
cout<<"No data procesed.\n";
else
{
cout<<"Item read:"<<count<<endl;
cout<<"Sum:"<<sum<<endl;
cout<<"Average:"<<sum/count<<endl;
}

system("pause");
return 0;

}

我已经在我的目录下建立了相应我要输入的文件名并存放了数据
但是运行后系统总是提醒我或是无法打开文件
也就是inFile.is_open()返回FALSE
为什么呢????????

c:\\data.txt
not c:\data.txt.
要多加一个\

我看了一下,只需把你的程序里面的
while(inFile.good())
{
++count;
sum+=value;
inFile>>value;
}
的条件该为inFile就可以了.
还要注意你的路径的输入格式(后缀).
比如:
f:\qw.txt

改过之后的程序如下:
#include<iostream>
#include<fstream>
#include<cstdlib>

const int SIZE=60;

int main()
{
using namespace std;
char filename[SIZE];
ifstream inFile;

cout<<"Enter name of data file:";
cin.getline(filename,SIZE);
inFile.open(filename);
if(!inFile.is_open())
{
cout<<"Could not open the file "<<filename<<endl;
cout<<"Program terminating.\n";

}

double value;
double sum=0.0;
int count=0;
//cout<<"Ener the value:";
inFile>>value;
while(inFile)
{
++count;
sum+=value;
inFile>>value;
}

if(inFile.eof())
cout<<"End of file reached.\n";
else if(inFile.fail())
cout<<"Input terminated by data mimatch.\n";
else
cout<<"Input terminated for unknow reasons.\n";
if(count==0)
cout<<"No data procesed.\n";
else
{
cout<<"Item read:"<<count<<endl;
cout<<"Sum:"<<sum<<endl;
cout<<"Average:"<<sum/count<<endl;
}

system("pause");
return 0;

}

#include<iostream>
#include<fstream>
#include<cstdlib>
#include<string>
using namespace std;
const int SIZE=60;

int main()
{

string filename;//直接把文件名定义成string ，不是更简单吗？！
ifstream inFile;
cout<<"Enter name of data file:";
cin>>filename;
inFile.open(filename.c_str());//把C++风格的字符串转换成C风格的字符串。打开的文件名一定要是C风格的字符串
if(!inFile)
{
cout<<"Could not open the file "<<filename<<endl;
cout<<"Program terminating.\n";

}

double value;
double sum=0.0;
int count=0;

inFile>>value;
while(inFile.good())
{
++count;
sum+=value;
inFile>>value;
}

if(inFile.eof())
cout<<"End of file reached.\n";
else if(inFile.fail())
cout<<"Input terminated by data mimatch.\n";
else
cout<<"Input terminated for unknow reasons.\n";
if(count==0)
cout<<"No data procesed.\n";
else
{
cout<<"Item read:"<<count<<endl;
cout<<"Sum:"<<sum<<endl;
cout<<"Average:"<<sum/count<<endl;
}

system("pause");
return 0;

}

我运行的时候可以了，你看看！

上面的程序我运行了的,是可以的呀.不晓得 你的环境那里出了问题哈