Slide 2.4: Opening and closing files (cont.)

Opening and Closing Files (Cont.)

using namespace std;
In a strict ANSI compliant compiler, the standard library is in the std namespace. This means that all standard library symbols either need to qualified with the std::prefix (e.g. std::cout), or simply moved into the global namespace with the using namespace directive.

ostream << const char * str;
The operator << inherited from the class ostream performs a formatted output operation (insertion). cout is the standard output stream.

void close ( );
It is a method of the class fstream and closes a file. The stream's file buffer is released from its association with the currently open file. Files are usually closed automatically by the operating system when a program terminates normally.

int system ( const char * command );
This command invokes command interpreter to execute a command of the host-machine, which is a Unix machine for our case. Once terminated, the interpreter gives back control to the program.

/bin/cat
It is a Unix shell command for concatenating and displaying files. For more Unix commands, check the manual pages. The following demonstration shows how the system command works:
#include <cstdlib> using namespace std; int main( ) { system( "" ); }