编写函数计算N!,调用该函数计算下式的值:
编写函数计算N!,调用该函数计算下式的值:S=1+1/(1+4!)+1/(1+4!+7!)+`````+1/(1+4!+7!+```````+19!)
程序代码:#include "stdio.h"
double fact(int x)
{
double item=1,i;
for (i=1;i<=x;i++)
item*=i;
return item;
}
double add(int y)
{
double sum;
int i;
sum=0;
for (i=1;i<=y;i=i+3)
sum+=1/fact(i);
return sum;
}
void main()
{
double s;
s=add (19);
printf("the result is : %lf\n",s);
}