#include <stdio.h>
long long fun(int n);    

int main() {
    int n;
    long long f;
    
    while(scanf("%d", &n) != EOF) {
        f = fun(n);  
        printf("n = %d, f = %lld\n", n, f);
    }
    
    return 0;
}

long long fun(int n){
    if(n==1)
    {return 1;
    }
    else
    {return 2*fun(n-1)+1;
    }
     
}

// 利用局部static变量计算阶乘
 
#include <stdio.h>
long long fac(int n); // 函数声明
 
int main() {
    int i,n;
     
    printf("Enter n: ");
    scanf("%d", &n);
     
    for(i=1; i<=n; ++i)
        printf("%d! = %lld\n", i, fac(i));
         
    return 0;
}
 
// 函数定义
long long fac(int n) {
    static long long p = 1;
    printf("p=%lld\n",p); 
   p = p*n;
    
   return p;
}

#include<stdio.h>
int func(int, int);
 
int main() {
    int k=4,m=1,p1,p2;
     
    p1 = func(k,m) ;
    p2 = func(k,m) ;
    printf("%d,%d\n",p1,p2) ;
     
    return 0;
}
 
int func(int a,int b) {
    static int m=0,i=2;
     
    i += m+1;
    m = i+a+b;
     
    return (m);
}

#include <stdio.h>
#define N 1000
int fun(int n,int m,int bb[N]) {
    int i,j,k=0,flag;
    
    for(j=n;j<=m;j++) {
          flag=1;   
        for(i=2;i<j;i++)
            if(j%i==0) {  
                   flag=0;
                   break;
        }
        if(flag!=0) 
           bb[k++]=j;
    }
    return k;
}

int main(){
    int n=0,m=0,i,k,bb[N];
    
    scanf("%d",&n);
    scanf("%d",&m);
    
    for(i=0;i<m-n;i++)
        bb[i]=0;
        
    k=fun(n,m,bb); 
    
    for(i=0;i<k;i++)
        printf("%4d",bb[i]);
        
    return 0;
}

#include <stdio.h>
void dec2n(int x, int n);

int main() {
    int x;
    
    printf("输入一个十进制整数: ");
    scanf("%d", &x);
    
    dec2n(x, 2);
    dec2n(x, 8);
    dec2n(x, 16);
    
    return 0;
}
void dec2n(int x, int n) 
{
    int i;
    char m;
    int change[1000];
    
    for(i=0;x!=0;i++)
        {
            change[i]=x%n;
            x=x/n;
        }
    
    for(i=i-1;i>=0;i--)
    {
        if(change[i]>=10)
        {
            m=55+change[i];
            printf("%c",m);
        }
        else
        printf("%d",change[i]);
    }
    
    printf("\n");
}