Dear boosters, I discovered something that at least was new to me. It's a simple way of coding floating point constants s.t. 1. no overhead at all 2. no order dependencies occur 3. the context in which the constant appears decides the precision of the constants [important in template code] 4. whenever a narrowing or widening conversion is required, explicit action must be taken by the programmer to determine what he wants 5. all precisions of the constants co-exist, so there is no need for several headers Example: #include "math_constant.hpp" #include <iostream> #include <cmath> #include <iomanip> using namespace std; template< typename T > void test(); int main() { cout << setprecision( 10 ); test<float>(); test<double>(); test<long double>(); // cout << pi; // ambiguous cout << float( pi ) << " " << double( pi ) << " " << (long double)( pi ); // ok // int i = pi; // ambiguous int i = float( pi ); // ok cout << sqrt( float( pi ) ); } template< typename T > void test() { T two_pi = T(2) * pi; two_pi = T(pi) + pi; // note: pi operator X() pi is ambiguous T plus = T(1) + pi; T minus = pi - T(1); T divide = pi / T(2); T all = pi + T(3) - T(pi) * pi / T(3); // also ambiguous cout << T( pi ) << " "; } Any comments are more than welcome. I know there are several proposals for defining math constants, but I don't see what the big problems are (so please help me understand them :-) ) br Thorsten