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// Compute decimal Archimedes' constant Pi to arbitrary accuracy.
#include <cln/output.h>
#include <cln/real.h>
#include <cln/real_io.h>
#include <ctype.h>
#include <stdlib.h>
#include <string.h>
using namespace std;
using namespace cln;
static void
usage (ostream &os)
{
os << "Usage: pi [digits]\n";
os << "Compute decimal Archimedes' constant Pi to arbitrary accuracy.\n\n";
os << " --help display this help and exit\n";
os << " --version output version information and exit\n";
os << " --bibliography output recommended readings and exit\n";
}
int
main (int argc, char * argv[])
{
int digits = 100;
if (argc > 1) {
if (argc == 2 && !strcmp(argv[1],"--help")) {
usage(cout);
return 0;
}
if (argc == 2 && !strcmp(argv[1],"--version")) {
cout << "pi (cln) " << CL_VERSION_MAJOR << "." << CL_VERSION_MINOR << endl;
cout << "Written by Bruno Haible." << endl;
cout << endl;
cout << "Copyright (C) 1998-2001 Bruno Haible." << endl;
cout << "This is free software; see the source for copying conditions. There is NO" << endl;
cout << "warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE." << endl;
cout << endl;
return 0;
}
if (argc == 2 && !strcmp(argv[1],"--bibliography")) {
cout << "Recommended readings:\n";
cout << "\"Pi\", by Joerg Arndt and Christoph Haenel (1999)\n";
cout << "\"Pi: A Source Book\" by Lennart Berggren, Jonathan Borwein, Peter Borwein (1997)" << endl;
return 0;
}
if (argc == 2 && isdigit(argv[1][0])) {
digits = atoi(argv[1]);
} else {
usage(cerr);
return 1;
}
}
cl_F p = pi(float_format(digits));
// make CLN believe this number has default_float_format to suppress
// exponent marker which would be quite boring for 3.1416...
cl_print_flags cpf;
cpf.default_float_format = float_format(p);
print_real(cout, cpf, p);
cout << endl;
return 0;
}