Factorial_Imperative.fs

// F# calculating the factorial in imperative approach programming.
let Fact n = 
    let mutable x = n
    let mutable y = 1
    while x > 0 do
        y <- y * x
        x <- (x - 1)
    y

for i in 0 .. 10 do
    printfn "%02d! = %d" i (Fact i)

(* the output    
00! = 1                                                                                                                                                                                                                  
01! = 1                                                                                                                                                                                                                  
02! = 2                                                                                                                                                                                                                  
03! = 6                                                                                                                                                                                                                  
04! = 24                                                                                                                                                                                                                 
05! = 120                                                                                                                                                                                                                
06! = 720                                                                                                                                                                                                                
07! = 5040                                                                                                                                                                                                               
08! = 40320                                                                                                                                                                                                              
09! = 362880                                                                                                                                                                                                             
10! = 3628800
*)