fstream newsFile;
  newsFile.open("I:\\NewBrowserText.txt");

谢谢。我刚刚调的是这样的。成功了。
class txtRead{
private:
    fstream newsFile;
    int rows;
    int cols;
    char news;
public:
    void printTxt();
    void countNum();
    txtRead();
};

txtRead::txtRead(){
    newsFile.open("I:\\NewBrowserText.txt");
    if(!newsFile){
        cout<<"you get wrong file's address!"<<endl;
    }
}

谢谢

谢谢o(≧v≦)o~~好棒