// https://godbolt.org/z/6qfo4oYnr
#include <iostream>
#include <iomanip> // fixed, setprecision
int main() {
using std::cout;
cout << std::setprecision(30) << std::fixed; // always output 30 digits
cout << 1.111222333444555666777888999f << "\n"; // float literal
// output: 1.111222386360168457031250000000
cout << 1.111222333444555666777888999 << "\n"; // double is default
// Output: 1.111222333444555676607023997349
cout << 1.111222333444555666777888999d << "\n"; // double literal
// output: 1.111222333444555676607023997349
cout << 1.111222333444555666777888999L << "\n"; // long double
// output: 1.111222333444555666740784227731
}