這題沒啥好寫的,惡心的是結果還要乘以2,試了半天原來是這地方出錯,蛋疼…
![](https://img.laitimes.com/img/9ZDMuAjOiMmIsIjOiQnIsIiclRnblN2XjlGcjAzNfRHLGZkRGZkRfJ3bs92YsYTMfVmepNHL3tGVPp3YU5kMRpHW3BjMMBjVtJWd0ckW65UbM5WOHJWa5kHT20ESjBjUIF2X0hXZ0xCMx81dvRWYoNHLrdEZwZ1Rh5WNXp1bwNjW1ZUba9VZwlHdssmch1mclRXY39CXldWYtlWPzNXZj9mcw1ycz9WL49zZwpmLxIjMyEjM1YTM1AzMwEjMwIzLc52YucWbp5GZzNmLn9Gbi1yZtl2Lc9CX6MHc0RHaiojIsJye.jpg)
#include<stdio.h>
double fact(int a){
double ret=1.0,sum=0;
for(int i=1;i<=a;i++){
ret*=i;
}
return ret;
}
double fact1(int b){
double ret=1.0,sum=0;
for(int i=1;i<=b;i=i+2){
ret*=i;
}
return ret;
}
int main()
{
double fenzi=0,fenmu=1;
double fenzi1,fenmu2;
double last=1;
float sum=0.0,sum1;
double threshold;
scanf("%lf",&threshold);
do{
fenzi1=fact(fenzi);
fenmu2=fact1(fenmu);
last=fenzi1/fenmu2*1.0;
sum1=sum;
sum+=last;
fenzi++;
fenmu=fenmu+2;
}while(last>threshold);
printf("%.6f",sum*2);
return 0;
}
寫的有點亂,主要被乘2搞心态了…随便看看。