10696 - f91

Problem A - f91

Time Limit: 1 second

Background

McCarthy is a famous theorician of computer science. In his work, he defined a recursive function, called f91, that takes as input a positive integer N and returns a positive integer defined as follows:

• If N ≤ 100, then f91(N) = f91(f91(N+11));
• If N ≥ 101, then f91(N) = N-10.

 

The Problem

Write a program, that computes McCarthy's f91.

The Input

The input tests will consist of a series of positive integers, each integer is at most 1,000,000. There will be at most 250,000 test cases. Each number is on a line on its own. The end of the input is reached when the number 0 is met. The number 0 shall not be considered as part of the test set.

Output

The program shall output each result on a line by its own, following the format given in the sample output.

Sample input

500
91
0

Sample output

f91(500) = 490
f91(91) = 91

#include"stdio.h"
int main()
{ 
 int N;
 double f91(int n); //预声明函数；  
 while(scanf("%d",&N)&&N)//为符合题意；
  printf("f91(%d)=%.0lf\n",N,f91(N)); //输出时调用函数；
  return 0;
  }
double f91(int n)
{
 double y;
 if(n<=100)
 y=f91(f91(n+11));//递归函数；
 else y=n-10;  
 return y;  
    }