在文本文件中查找字符串并显示c++中的整行

Question

我希望我的程序在文本文件中查找学生姓名，然后显示该特定行。

我只是将文本文件的第一行作为 output 而不是我要查找的行。

void OTHERS::search_acc()
{
  string srch;
  string line;

  fstream Myfile;
  Myfile.open("STUDENTS", ios::in|ios::out);
  cout << "\nEnter Student Name: ";
  cin.ignore();
  getline(cin, srch);

  if(Myfile.is_open())                                //The problem is in this if block
  {
      getline(Myfile, line);
      line.find(srch, 0);
      cout << "\nSearch result is as follows: \n" << line << endl;
  }
  else
  {
    cout << "\nSearch Failed...  Student not found!" << endl;
    system("PAUSE");
  }  
}

另外，是否可以返回我在文本文件中查找的字符串的位置？

Answer 1

您需要循环读取所有行，并在其中搜索每一行，例如

if(Myfile.is_open())
{
  while(getline(Myfile, line))                 // read all the lines
    if (line.find(srch) != std::string::npos)  // search each line
      cout << "\nFound on this line: \n" << line << endl;
}

Answer 2

int line=0;
while(!Myfile.eof()){
    getline(Myfile, line);
    line.find(srch, 0);
    ++line;
}
//this line will tell you the line number
cout << "\nSearch result is as follows: \n" << line << endl;

你正在阅读一行阅读整个文件