Модератор: Модераторы разделов
Код: Выделить всё
#include <stdio.h>
void main (int argc, char **argv)
{
unsigned int n, i = 1, result = 1;
if (argc < 2)
return;
n = atoi (argv[1]);
while (1)
{
printf ("%d\n", i);
result *= i++;
if (i > n)
break;
}
printf ("%u! = %u\n", n, result);
}
Код: Выделить всё
alexander@goblin /tmp $ cat 1.c
#include <stdio.h>
int main (int argc, char **argv)
{
printf ("%u %u\n", sizeof(long long), sizeof(long));
}
alexander@goblin /tmp $ gcc -m32 1.c
alexander@goblin /tmp $ ./a.out
8 4
alexander@goblin /tmp $ gcc -m64 1.c
alexander@goblin /tmp $ ./a.out
8 8Shell
$ bc
bc 1.06.95
Copyright 1991-1994, 1997, 1998, 2000, 2004, 2006 Free Software Foundation, Inc.
This is free software with ABSOLUTELY NO WARRANTY.
For details type `warranty'.
define f (x) {
if (x <= 1) return (1);
return (f(x-1) * x);
}
f(1)
1
f(10)
3628800
f(13)
6227020800
f(34)
295232799039604140847618609643520000000
2^32
4294967296
2^64
18446744073709551616
The length modifier
Here, "integer conversion" stands for d, i, o, u, x, or X conversion.
hh A following integer conversion corresponds to a signed char or unsigned char argument, or a follow‐
ing n conversion corresponds to a pointer to a signed char argument.
h A following integer conversion corresponds to a short int or unsigned short int argument, or a fol‐
lowing n conversion corresponds to a pointer to a short int argument.
l (ell) A following integer conversion corresponds to a long int or unsigned long int argument, or a
following n conversion corresponds to a pointer to a long int argument, or a following c conversion
corresponds to a wint_t argument, or a following s conversion corresponds to a pointer to wchar_t
argument.
ll (ell-ell). A following integer conversion corresponds to a long long int or unsigned long long int
argument, or a following n conversion corresponds to a pointer to a long long int argument.
L A following a, A, e, E, f, F, g, or G conversion corresponds to a long double argument. (C99
allows %LF, but SUSv2 does not.)
q ("quad". 4.4BSD and Linux libc5 only. Don't use.) This is a synonym for ll.
j A following integer conversion corresponds to an intmax_t or uintmax_t argument.
z A following integer conversion corresponds to a size_t or ssize_t argument. (Linux libc5 has Z
with this meaning. Don't use it.)
t A following integer conversion corresponds to a ptrdiff_t argument.
The SUSv2 only knows about the length modifiers h (in hd, hi, ho, hx, hX, hn) and l (in ld, li, lo, lx,
lX, ln, lc, ls) and L (in Le, LE, Lf, Lg, LG).
Код: Выделить всё
#include <stdio.h>
void main (int argc, char **argv)
{
unsigned long long int n, i = 1, result = 1;
if (argc < 2)
return;
n = atoi (argv[1]);
while (1)
{
result *= i++;
if (i > n)
break;
printf ("%llu! = %llu\n", i, result);
}
}Код: Выделить всё
factorial 35
2! = 1
3! = 2
4! = 6
5! = 24
6! = 120
7! = 720
8! = 5040
9! = 40320
10! = 362880
11! = 3628800
12! = 39916800
13! = 479001600
14! = 6227020800
15! = 87178291200
16! = 1307674368000
17! = 20922789888000
18! = 355687428096000
19! = 6402373705728000
20! = 121645100408832000
21! = 2432902008176640000
22! = 14197454024290336768
23! = 17196083355034583040
24! = 8128291617894825984
25! = 10611558092380307456
26! = 7034535277573963776
27! = 16877220553537093632
28! = 12963097176472289280
29! = 12478583540742619136
30! = 11390785281054474240
31! = 9682165104862298112
32! = 4999213071378415616
33! = 12400865694432886784
34! = 3400198294675128320
35! = 4926277576697053184
ну, вообще-то:
уже точно неправильный результат даже на глаз — в конце числа должны быть нули·
Код: Выделить всё
#include <stdio.h>
#include <gmp.h>
int main(void)
{
unsigned int n, i;
char buf[256];
scanf("%u", &n);
mpz_t fctr;
mpz_init_set_ui(fctr, 1);
for (i = 2; i <= n; i++) {
mpz_mul_ui(fctr, fctr, i);
printf("%u!: %s\n", i, mpz_get_str(buf, 10, fctr));
}
mpz_clear(fctr);
return 0;
}Код: Выделить всё
#include <stdio.h>
#include <stdlib.h>
#include <memory.h>
#define BASE 10000
#define BASE_LOG 4
typedef struct
{
unsigned int count;
unsigned int* num;
} big;
void big_atleast(big* x, unsigned int sz)
{
if (x->count < sz) {
unsigned int nc = 1, i;
while (nc < sz)
nc <<= 1;
unsigned int* nn = (unsigned int*)malloc(nc * sizeof(unsigned int));
for (i = 0; i < x->count; i++)
nn[i] = x->num[i];
for (; i < nc; i++)
nn[i] = 0;
x->count = nc;
free((void*)x->num);
x->num = nn;
}
}
void big_init(big* x, unsigned int n)
{
unsigned int i;
x->count = 0;
x->num = NULL;
big_atleast(x, 4);
for (i = 0; n; i++, n /= BASE) {
x->num[i] = n % BASE;
}
}
void big_mul(big* x, unsigned int n)
{
unsigned int c = 0, i, t;
for (i = 0; i < x->count; i++) {
t = x->num[i] * n + c;
x->num[i] = t % BASE;
c = t / BASE;
}
if (c) {
big_atleast(x, x->count+1);
x->num[i] = c;
}
}
void big_print(big* x)
{
int i;
int q = 0;
for (i = (int)x->count - 1; i >= 0 && !x->num[i]; i--) { }
if (i < 0)
i = 0;
printf("%u", x->num[i--]);
for (; i >= 0; i--) {
printf("%0*u", BASE_LOG, x->num[i]);
}
}
void big_free(big* x)
{
free((void*)x->num);
}
int main(void)
{
unsigned int n, i;
scanf("%u", &n);
big fctr;
big_init(&fctr, 1);
for (i = 2; i <= n; i++) {
big_mul(&fctr, i);
printf("%u!: ", i);
big_print(&fctr);
printf("\n");
}
big_free(&fctr);
}drBatty писал(а): ↑25.04.2012 11:46
вот я не думаю, что такой пассаж будет работать так же быстро, как и команда imul процессора. ИМХО раз так в 10..100 медленнее. Хотя если компилятор таки распарсит, что t % BASE === t & (BASE - 1), то да, взлетит более-менее. Хотя всё равно медленно, ибо даже 32 битный i80386 куда как быстрее множил на 32х битное число. По крайней мере раз в 10 быстрее, чем ваш код.