百科上搜到的：#include ＜cstdlib＞#include ＜iostream＞#include ＜fstream＞#define N 20010using namespace std;void mult (int *a,int b,int *s){
for (int i=N,c=0;i＞=0;i--)
{
int y=(*(a+i))*b+c;
c=y/10;
*(s+i)=y%10;
}}void divi (int *a,int b,int *s){
for (int i=0,c=0;i＜=N;i++)
{
int y=(*(a+i))+c*10;
c=y%b;
*(s+i)=y/b;
}}void incr(int *a,int *b,int *s){
for (int i=N,c=0;i＞=0;i--)
{
int y=(*(a+i))+(*(b+i))+c;
c=y/10;
*(s+i)=y%10;
}}bool eqs(int *a,int *b){
int i=0;
while (((*(a+i))==(*(b+i)))&&(i＜=N)) i++;
return i＞N;}int main(int argc, char *argv[]){
int lpi[N+1],lls[N+1],lsl[N+1],lp[N+1];
int *pi=lpi,*ls=lls,*sl=lsl,*p=lp;
for (int i=0;i＜=N;i++)*(pi+i)=*(ls+i)=*(sl+i)=*(p+i)=0;
memset(pi,0,sizeof(pi));
memset(ls,0,sizeof(ls));
memset(sl,0,sizeof(sl));
memset(p,0,sizeof(p));
*pi=*ls=*sl=1;
for (int i=1;true;i++)
{
mult(ls,i,sl);
divi(sl,2*i+1,ls);
incr(pi,ls,p);
if (eqs(pi,p)) break;
int *t;
t=p;
p=pi;
pi=t;
if (i%50==0) cout ＜＜ i ＜＜ "";
}
cout ＜＜ endl;
mult(p,2,pi);
ofstream fout("pi.txt");
fout << *pi << ".";
for (int i=1;i<=N;i++)
{
fout << *(pi+i);
if (i%10==0) fout ＜＜ " ";
if (i%80==0) fout ＜＜ endl;
}
return EXIT_SUCCESS;}参考资料：百度百科
已赞过已踩过<
|
