Finder første tal af en primtal faktor opløsning, fx givet 60 = 2 x 2 x 3 x 5, giver den det første tal, altså 2

Primtal.bf

// Første tal til primtal faktorisering af Kresten den 29/08/20

// 0th;   1st;   2nd;  3rd;  4th;  5th; 6th; 7th
// tæller; 0; dividend; 0; divisor; 0;   0;   0

+ // tæller = 1

>> // dividend
++++ +++ // 2nd = stdin

>>> // 5th
+ // = non zero

[
	// reset 5th position to 0th
	[
		-
	]
	<[ // reset 4th position to 0th
		-
	]

	<<<< // tæller
	+ // plus lig med 1

	//  move 0th to 4th and 8th
	[
		>>>> +
		>>>> +
		<<<< <<<< -
	]
	>>>> >>>>[ // move 8th to 0th
		<<<< <<<< + // 1th plus plus
		>>>> >>>> - // 8th
	]
	
	// gammel kode her
	
	// set 3th to 0
	<<<< <[
		-
	]
	<<< // 0th

	// INPUT
	// 1st;  2nd;   3rd; 4th;   5th; 6th; 7th
	//  0; dividend; 0; divisor; 0;   0;   0
	// mod
	>> // 2nd
	[
		>+ // 3rd plus 1
		>- // 4th minus 1
		>+ // 5th plus 1
		< // 4th
		[>] // goto next 0; 6?
		>[ // 7?
			<+
			>-
		]
		<<
		[<]
		>-
	]
	// 0th;   1st; 2nd;    3rd;      4th;       5th; 6th; 7th
	// tæller; 0;   ud:0;   dividend; d minus n%d; n%d;  0;   0
	
	<< // 0th
	
	// 2nd = 3rd; 3rd = 0
	>>>[
		<+
		>-
	]
	>> // 5th
]

<<<<<. // 0th = stdout



// old code
//Copy 3rd to 2nd; for at flytte input
	//  move 3rd to 2nd and 8th
	[
		-
		<+ // 2nd plus plus
		>>>> >>+ // 8th plus plus
		<<<< < // 3rd
	]
	>>>> >[ // move 8th to 3rd
		-
		<<<< <+ // 3rd plus plus
		>>>> > // 8th
	]