全排列

//计算1！+3！+······+n！的值

#include <stdio.h>
void main()
{
int n=1,m,k;
double sum1,sum=0;
printf("计算1+3！+······+n！的值\n");
printf("请输入一个正整数：");
scanf("%d",&m);
BE1:
sum1=1;
for(k=1;k<=n;k++)
{
sum1=sum1*k;
}
while(n<=m)
{
n=n+2;
sum=sum+sum1;
goto BE1;
}
printf("1+3!+······+%d!=%.2f\n",n-2,sum);
}

 

 

 

 

//计算2！+4！+······+n！的值

#include <stdio.h>
void main()
{
int n=0,m,k;
double sum1,sum=0;
printf("计算2！+4！+······+n！的值\n");
printf("请输入一个正整数：");
scanf("%d",&m);
BE1:
sum1=1;
for(k=1;k<=n;k++)
{
sum1=sum1*k;
}
while(n<=m)
{
n=n+2;
sum=sum+sum1;
goto BE1;
}
printf("2!+4!+······+n!=%.2f\n",sum-1);
}