prog19_02.cpp

c++最经典的入门书籍

// Program 19.2 Reading the primes file  File: prog19_02.cpp
#include <fstream>
#include <iostream>
#include <iomanip>
using std::cout;
using std::endl;


int main() {
  const char* filename = "C:\\JunkData\\primes.txt";   // Name of the file to read
  std::ifstream inFile(filename);                      // Create input stream object

  // Make sure the file stream is good
  if(!inFile) {
    cout << endl << "Failed to open file " << filename;
    return 1;
  }

  long aprime = 0;
  int count = 0;
  while(!inFile.eof()) {                               // Continue until EOF is found
    inFile >> aprime;                                  // Read a value from the file
    cout << (count++ % 5 == 0 ? "\n" : "") << std::setw(10) << aprime;
  }
  cout << endl;
  return 0;
}