Mega Code Archive

Precision of double

#include <iomanip> #include <iostream> using namespace std; int main( ){ const double x = .39; const double y = 27; cout<< ".39, fixed, 1 decimal place: " << fixed << setprecision( 1 ) << x << endl << ".39, fixed, 2 decimal places: " << setprecision( 2 ) << x << endl << ".39, fixed, 3 decimal places: " << setprecision( 3 ) << x << endl << endl << ".39, scientific, 1 decimal place: " << scientific << setprecision( 1 ) << x << endl << ".39, scientific, 2 decimal places: " << setprecision( 2 ) << x << endl << ".39, scientific, 3 decimal places: " << setprecision( 3 ) << x << endl << endl // return to default floating-point output format << resetiosflags( ios::fixed | ios::scientific ) << setprecision( 6 ) << ".39 and 27., default: " << x << " " << y << endl << ".39 and 27., default, 1 decimal place: " << setprecision( 1 ) << x << " " << y << endl << ".39 and 27., default, 2 decimal places: " << setprecision( 2 ) << x << " " << y << endl << ".39 and 27., default, 3 decimal places: " << setprecision( 3 ) << x << " " << y << endl << endl << ".39 and 27., default, decimal point: " << showpoint << x << " " << y << endl << ".39 and 27., default, decimal point, 1 decimal place: " << setprecision( 1 ) << x << " " << y << endl << ".39 and 27., default, decimal point, 2 decimal places: " << setprecision( 2 ) << x << " " << y << endl << ".39 and 27., default, decimal point, 3 decimal places: " << setprecision( 3 ) << x << " " << y << endl; }