strfile.cpp

来自「This is the second part of that lab manu」· C++ 代码 · 共 43 行

//: C05:Strfile.cpp
// From "Thinking in C++, 2nd Edition, Volume 2"
// by Bruce Eckel & Chuck Allison, (c) 2001 MindView, Inc.
// Available at www.BruceEckel.com.
// Stream I/O with files
// The difference between get() & getline()
//{L} ../TestSuite/Test
#include "../require.h"
#include <fstream>  
#include <iostream>
using namespace std;

int main() {
  const int sz = 100; // Buffer size;
  char buf[sz];
  {
    ifstream in("Strfile.cpp"); // Read
    assure(in, "Strfile.cpp"); // Verify open
    ofstream out("Strfile.out"); // Write
    assure(out, "Strfile.out");
    int i = 1; // Line counter

    // A less-convenient approach for line input:
    while(in.get(buf, sz)) { // Leaves \n in input
      in.get(); // Throw away next character (\n)
      cout << buf << endl; // Must add \n
      // File output just like standard I/O:
      out << i++ << ": " << buf << endl;
    }
  } // Destructors close in & out

  ifstream in("Strfile.out");
  assure(in, "Strfile.out");
  // More convenient line input:
  while(in.getline(buf, sz)) { // Removes \n
    char* cp = buf;
    while(*cp != ':')
      cp++;
    cp += 2; // Past ": "
    cout << cp << endl; // Must still add \n
  }
} ///:~