#include <itpp/itcomm.h>using namespace itpp;int main(){  // Declare the it_file class  it_file ff;  // Open a file with the name "it_file_test.it"  ff.open("it_file_test.it");  // Create some data to put into the file  vec a = linspace(1, 20, 20);  // Put the variable a into the file. The Name("a") tells the file class  // that the next variable shall be named "a".  ff << Name("a") << a;  // Force the file to be written to disc. This is useful when performing  // iterations and ensures that the information is not stored in any cache  // memory. In this simple example it is not necessary to flush the file.  ff.flush();  // Close the file  ff.close();  // Exit program  return 0;}