大数阶乘.cpp

大数阶乘

// 大数阶乘.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"
#include "stdio.h"
#include "malloc.h"

const MAX=1000;
void pnext(int a[],int k)
{
	int *b, m=a[0],i,j,r,carry;
    b=(int *)malloc(sizeof(int)*(m+1));

	for(i=1;i<=m;i++) b[i]=a[i];
    for(j=1;j<k;j++)
	{
		for(carry=0,i=1;i<=m;i++)
		{ 
			r= (i<=a[0] ? a[i]+b[i] : a[i]) + carry;
			a[i]=r % 10; carry=r / 10;
		}
		if(carry)
			a[++m]=carry;
	}
	free(b);
	a[0]=m;

}
void showa(int *a,int k)
{
	int i;
	printf("% 4d !=",k);
    for(i=a[0];i>0;i--)
		printf("%d", a[i]);
		printf("\n\n");
	
}

int main(int argc, char* argv[])
{
    int a[MAX],n,k;
    printf("input n:");
    scanf("%d",&n);
	a[0]=1;a[1]=1; showa(a,1);
    for(k=2;k<=n;k++)
	{
		pnext(a,k);
		showa(a,k);
	}
	return 0;
}