1.3 KiB
1.3 KiB
Exercise 2.2 (Power)
(*First version ; 6 multiplications*)
# let power28(x) =
let x2 = x + x in
let x4 = x2*x2 in
let x8 = x4*x4 in
let x16 = x8*x8 in
x16*x8*x4 ;;
(*Second version ; 27 multiplications*)
# let power28(x) = x*x*x*x*x*x...*x ;;
(*Third version ; 11 multiplications*)
# let power28(x) =
let sq(x) = x*x in
let pow4(x) = sq(sq(x)) in
pow4(pow4(x))*sq(pow4(x))*pow4(x);;
(*Fourth version ; 7 multiplications*)
# let power28(x)=
let sq(x) = x+x in
let p4=sq(sq(x)) in
sq(sq(p4))*sq(p4)*p4;;
Exercise 2.3
# (*my verison*)
# let mirror(n) = let diz = n/10 and uni = n mod 10 in uni*10 + diz;;
val mirror : int -> int = <fun>
# (*teatcher version*)
# let mirror n = 10 *(n mod 10)+n/10;;
val mirror : int -> int = <fun>
# let abba(n) = n*100 + mirror(n) ;;
val abba: int -> int = <fun>
# let stammer(n) = abba(mirror(n)) * 10 000 + abba(n) ;;
val stammer: int -> int = <fun>
Exercice 2.6
let sec_of_time h m s =
h*3600 + m*60 + s ;;
let time_of_sec s =
let hours = s/3600 in let minutes = (s - hours*3600)/60 in let seconds = s - hours *3600 - minutes * 60 in (hours, minutes, seconds);;
let add_times h1 m1 s1 h2 m2 s2 =
let sec1 = sec_of_time(h1 m1 s1) and sec2 = sec_of_time(h2 m2 s2) in let resultsec = sec1 + sec2 in time_of_sec(resultsec) ;;