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){
    long long result;
    if(n==0)
    result=0;
    else if(n==1)
    result=1;
    else
    result=2*fun(n-1)+1;
    return result;}

#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>
#include <stdlib.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];
    
    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 t[100],i,count=0;
    for(i=0;x!=0;i++){
        t[i]=x%n; 
        x=x/n;
        count++;
    }
    
    if (t[i]>9)
    switch(t[i]){
             
        case 10:t[i]=‘A‘;break;
        case 11:t[i]=‘B‘;break;
        case 12:t[i]=‘C‘;break;
        case 13:t[i]=‘D‘;break;
        case 14:t[i]=‘E‘;break;        
        case 15:t[i]=‘F‘;break;
        default:break;
    }
    
    printf("%d进制: ",n);
    for(i=count-1;i>=0;i--){
        
       printf("%X",t[i]);
        
    }
    printf("\n");
    
     
}