#include<bits/stdc++.h>
using namespace std;
int n,a[1100],k;
int main()
{
	cin>>n;
	a[1]=1;
	for(int i=2;i<=n;i++)
	{
		for(int j=1;j<=1000;j++)
		{
			a[j]=a[j]*i+k;
			k=a[j]/10;
			a[j]%=10;
		}
	}
	cout<<n<<"!=";
	k=1000;
	while(!a[k]) k--;
	for(int i=k;i>=1;i--) cout<<a[i];
}

#include<bits/stdc++.h> #define ll long long #define un unsigned #define int long long #define db double #define st string #define ct const #define xh(a,b,c) for(int a=b;a<=c;a++) #define wx while(1) #define dn(a,b,c) for(int a=b;a>=c;a--) using namespace std; un ll ans[1010]; int n; void print(){ int k=1000; while(!ans[k])k--; dn(i,k,1)cout<<ans[i]; } void dfs(int i){ i++; if(i==n+1){ print(); return ; } int jw=0; xh(j,1,1000){ ans[j]=ans[j]*i+jw; jw=ans[j]/10; ans[j]%=10; } dfs(i); } signed main(){ cin>>n; ans[1]=1; printf("%d!=",n); dfs(0); return 0; }

普通高精

#include<bits/stdc++.h>
using namespace std;
int n;
int num[1000005],cnt;
signed mian(){
	ios::sync_with_stdio(0),cin.tie(0),cout.tie(0);
	cin>>n;
	num[1]=1;cnt=1;
	for(int i=2;i<=n;i++){
		for(int j=1;j<=cnt;j++) num[j]*=i;
		for(int j=1;j<cnt;j++) if(num[j]>9) num[j+1]+=num[j]/10,num[j]%=10;
		while(num[cnt]>9) num[cnt+1]+=num[cnt]/10,num[cnt]%=10,cnt++;
	}
	cout<<n<<"!=";
	for(int i=cnt;i>=1;i--) cout<<num[i];
	return 0;
}
//if you copy this code,you will get a big surprise!

#include <bits/stdc++.h> using namespace std; int a[1000]; int main() {

int n,i,j,c=0,p;
cin>>n;
cout<<n<<"!=";
if(n==1)
{
	cout << "1";
}
else
{
	a[0]=1; 
	for(i=2;i<=n;++i)
	{
		c=0;
		for(j=0;j<1000;++j)
		{ 
			p=a[j]*i+c;
			a[j]=p%10;
			c=p/10;
		}
	}
	for(i=999;i>=0;--i)
	if(a[i]>0)break;
	for(j=i;j>=0;--j)
	
	cout<<a[j];
}
return 0;

}