Week4

Programming Assignment 2

• Extension: Due 11/7 11:55pm, don't be late!
• Environment Variables
  • "setenv VARIABLE_NAME value" to set environment variables
  • footprints will be found in /home/cs40at/footprint
  • available as a third parameter of main as a char* array
  • or use getenv()
• Streams
  • filestream - fstream, string stream - sstream

#include <iostream>
#include <fstream>
#include <string>
#include <sstream>

using namespace std;

int main (int argc, char* argv[], char* envp[]) {
  string filename1, filename2;
  fstream* filestream = new fstream();
  string curline;
  string file_contents;

  // print out all the environment variables
  for(int i=0; envp[i] != NULL; i++) {
    cout << envp[i] << endl;
  }

  // get the value of a single environment variable
  cout << getenv("HOME") << endl;

  filename1 = filename2 = getenv("HOME");
  filename1 += "/foo";
  filename2 += "/bar";

  // filestream operations
  filestream->open(filename1.c_str(), fstream::in);
  while (getline(*filestream, curline)) {
    cout << curline << endl;
    file_contents += curline;
  }
  delete filestream;
  
  // a new filestream is needed for a new file
  filestream = new fstream();
  filestream->open(filename2.c_str(), fstream::out);
  *filestream << file_contents;
  delete filestream;

  // parsing an integer
  int one;
  int two;
  int three;
  string onetwothree = "1 2 3";
  stringstream* ss;
  ss = new stringstream(onetwothree);
  *ss >> one >> two >> three >> onepointone;
  cout << "one=" << one << " two=" << two << " three=" << three << endl;
}