实验四

#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 fun(n - 1) * 2 + 1;
    }
}

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

 
long long fac(int n) {
    static long long p = 1;
    
    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 == 1)
            bb[k++] = j;
    }
    return k;
}

int main() {
    int n = 0, m = 0, i, k, bb[N];

    while (scanf("%d %d", &n, &m) != EOF) {



        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]);
        printf("\n");
    }

    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);   // 函数调用: 把x转换成二进制输出 
    dec2n(x, 8);     // 函数调用: 把x转换成八进制输出
    dec2n(x, 16);    // 函数调用: 把x转换成十六进制输出
    
    return 0;
}

 
void dec2n(int x, int n) 
{
   int a[100];
   int i=0,m;
   
   do{
   
       a[i]=x%n;
       x=x/n;
       i++;
    }while(x!=0);
    
     if(a[i]>9){
        switch(a[i]){
        case 10:a[i]='A';break;
        case 11:a[i]='B';break;
        case 12:a[i]='C';break;
        case 13:a[i]='D';break;
        case 14:a[i]='E';break;
        case 15:a[i]='F';break;  
         }
      }
      
      m=i-1;
      for(m;m>=0;m--)
        printf("%X",a[m]);    
    printf("\n");
}