Real Big Water Problem

题目描述

If you have solved the small water problem,let's see this big one.If you don't,I suggest you ignore this problem!
Also give you a positive integer n.
Function F_x satisfies:
   F_0 = cos{n}
   F_x = cosF_{x-1} (x>0)
Calculate F_n.

输入格式

The input contains no more than 20 test cases.
For each test case,the only line consists of one integer n.
0<=n<=10^30.

输出格式

For each given n,print the answer in a single line.The result should be rounded to six decimal places.

输入样例

0
1
2
输出样例

1.000000
0.857553
0.610065
 

#include <iostream>

#include <cstdio>

#include<cmath>

#include<cstdlib>

#include<cstring>

using namespace std;

int function(double result,int t,int p){

  result=cos(result);

  if(t==p)printf("%.6lf\n",result);

  else function(result,t+1,p);

}

int main(){

  char n[100];

  double result;

  while(cin>>n){

    if(strlen(n)<=3){

      int t=0;

      int p=atoi(n);

      result=p;

      function(result,t,p);

    }

    else cout<<"0.739085"<<endl;

  }

  return 0;

}