#define _CRT_SECURE_NO_DEPRECATE
#include<stdio.h>
#include<string.h>
#define max 22
double a[max];

int main()
{
    int T, n, i, j, m;
    double k;
    a[1] = 0; a[2] = 1;
    for (i = 3; i <= 20; i++){
        a[i] = (i - 1)*(a[i - 1] + a[i - 2]);
    }
    printf("信封个数           排列个数              全排错个数                全排错概率\n");
    for (n = 1; n < 21;n++){
        k = 1;
        for (i = 2; i <= n; i++){
            k = k*i;
        }
    
        printf("%3d: %21.0lf,%21.0lf,%21.2lf%%\n",n,k,a[n],100.0 * a[n] / k);
    }
    getchar();
    getchar();
    //system("pause");
    return 0;
}