Files and Streams in C++

• Files are secondary storage or persistent storage; data remains in tact after computer is shut down
• We can save input in a file so that the next time the program is run we don't have to type it in again; Lab #2
• We can save output in a file so we don't have to run the program to generate the values again; Lab #4
• All real programs use files
• Files are used in conjunction with streams; input streams and output streams (reading and writing)
• cin and cout are streams; using files is very similar (almost identical) to using cin and cout
• We include iostream.h so we can use cin and cout; we include fstream.h so we can declare file input and output streams

  #include <iostream.h> // cin/cout streams
  #include <fstream.h>  // file streams

  ofstream outFile;     // declare an output file stream

  cout << "This writes to the display screen";
  outFile << "This writes to a disk file";