RosettaCodeData/Task/Factorial-primes/XPL0/factorial-primes.xpl0
2023-07-01 13:44:08 -04:00

42 lines
862 B
Text

func IsPrime(N); \Return 'true' if N is prime
real N; int I;
[if N <= 2. then return N = 2.;
if Mod(N, 2.) = 0. then \even\ return false;
for I:= 3 to fix(sqrt(N)) do
[if Mod(N, float(I)) = 0. then return false;
I:= I+1;
];
return true;
];
func real Factorial(N); \Return N!
int N; real F;
[F:= float(N);
while N > 1 do
[N:= N-1;
F:= F * float(N);
];
return F;
];
int N, C; real F;
[N:= 1; C:= 0;
Format(1, 0);
repeat F:= Factorial(N);
if IsPrime(F-1.) then
[IntOut(0, N);
Text(0, "! - 1 = ");
RlOut(0, F-1.);
CrLf(0);
C:= C+1;
];
if IsPrime(F+1.) then
[IntOut(0, N);
Text(0, "! + 1 = ");
RlOut(0, F+1.);
CrLf(0);
C:= C+1;
];
N:= N+1;
until C >= 10;
]