> ruhatadiyaman wrote:
> > thanks for all replies. i tried them but still the
> > problem is continuing. this is my code with 'unsigned
> > long int';
> > /*factorial*/
<snip>
> > so after 13 the results are wrong :(
> > otherwise i confused with usage of long double.
% type fact.c
#include <stdio.h>
#include <stdlib.h>
void out_of_memory(void)
{
fprintf(stderr, "out of memory!\n");
exit(EXIT_FAILURE);
}
int main(int argc, char **argv)
{
unsigned *a;
size_t i, len, cap;
unsigned long c, n, max_n;
if (argc != 2) exit(0);
max_n = strtoul(argv[1], 0, 10);
if (max_n < 2 || max_n > 9999) exit(0);
cap = 1;
a = malloc(cap * sizeof *a);
if (!a) out_of_memory();
len = 1;
a[0] = 1;
for (n = 2; n <= max_n; n++)
{
for (c = 0, i = 0; i < len; i++)
{
c = a[i] * n + c;
a[i] = c % 10000;
c /= 10000;
}
while (c)
{
if (len == cap)
{
if (cap > ((size_t)-1)/2) out_of_memory();
cap *= 2;
a = realloc(a, cap * sizeof *a);
if (!a) out_of_memory();
}
a[len++] = c % 10000;
c /= 10000;
}
}
printf("%4u", a[len - 1]);
for (c = 1, i = len - 1; i-- > 0; )
{
printf("%04u", a[i]);
if (++c == 16) { putchar('\n'); c = 0; }
}
if (c) putchar('\n');
free(a);
return 0;
}
% acc fact.c -o fact.exe
% fact 1000
4023872600770937735437024339230039857193748642107146325437999104
2993851239862902059204420848696940480047998861019719605863166687
2994808558901323829669944590997424504087073759918823627727188732
...
00000000
> > i wrote this simple code which is below;
> > #include<stdio.h>
> > int main()
> > {
> >
> > long double x, y;
> > scanf("%Lf", &x);
> > scanf("%Lf", &y);
Try checking the return value of scanf.
> > printf("x=%Lf y=%Lf\n", x, y);
> > printf("result=%Lf", x*y);
> > getch();
> > }
> >
> > when i run it,for example, i give 2 for x and 4 for y,the
> > program gives this;
> > x=2.000000 y=0.000000
> > result=-2.000000
> >
> > what's this?
I don't know.
% type ld.c
#include<stdio.h>
int main(void)
{
long double x, y;
if (scanf("%Lf%Lf", &x, &y) == 2)
{
printf("x=%Lf y=%Lf\n", x, y);
printf("result=%Lf", x*y);
}
return 0;
}
% acc ld.c -o ld.exe
% ld
2 4
x=2.000000 y=4.000000
result=8.000000
Thomas Hruska <thru...@...> wrote:
> You could also use unsigned long long int and %llu (minimum
> of 64-bits, which will be more accurate than 'float' or
> 'double'). The following is worth keeping around as well
> for future reference:
>
> <http://cubicspot.blogspot.com/2009/03/unsigned-long-long-long-long-long-int.html>
"Thankfully 'float' and 'double' use the IEEE floating point
standard."
That is not a requirement of either C or C++.
"The lack of being able to declare how many bits/bytes we
need for integer representation is silly and only going
to get sillier as int sizes get larger." etc...
Have you heard of <stdint.h>?
--
Peter
