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Function `std.numeric.decimalToFactorial`

This function transforms decimal value into a value in the factorial number system stored in fac.


						
				ulong decimalToFactorial
				(
				

				  ulong decimal,
				

				  ref ubyte[21] fac
				

				) pure nothrow @nogc @safe;

A factorial number is constructed as: fac[0] * 0! + fac[1] * 1! + ... fac[20] * 20!

Parameters

Name	Description
decimal	The decimal value to convert into the factorial number system.
fac	The array to store the factorial number. The array is of size 21 as `ulong.max` requires 21 digits in the factorial number system.

Returns

A variable storing the number of digits of the factorial number stored in fac.

Example

ubyte[21] fac;
size_t idx = decimalToFactorial(2982, fac);

writeln(fac[0]); // 4
writeln(fac[1]); // 0
writeln(fac[2]); // 4
writeln(fac[3]); // 1
writeln(fac[4]); // 0
writeln(fac[5]); // 0
writeln(fac[6]); // 0

Authors

Andrei Alexandrescu, Don Clugston, Robert Jacques, Ilya Yaroshenko

License

Boost License 1.0.