实验三

实验1.1 随机打印hi,november

#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <windows.h>
#define N 80
void print_text(int line, int col, char text[]); 
void print_spaces(int n); 
void print_blank_lines(int n); 
int main() {
int line, col, i;
char text[N] = "hi, November~";
srand(time(0)); 
for(i = 1; i <= 10; ++i) {
line = rand() % 25;
col = rand() % 80;
print_text(line, col, text);
Sleep(1000); 
}
return 0;
}

void print_spaces(int n) {
    int i;
for(i = 1; i <= n; ++i)
printf(" ");
}

void print_blank_lines(int n) {
int i;
for(i = 1; i <= n; ++i)
printf("\n");
}

void print_text(int line, int col, char text[]) {
print_blank_lines(line-1); 
print_spaces(col-1); 
printf("%s", text); 
}

实验2.1
static 1.静态局部变量，变量的存储区域由栈变为静态常量区，生命周期由局部变为全局，作用域不变


#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!=%11d\n",i,fac(i));
        
    }
    
    
    return 0;
}  
long long fac(int n){
    static long long p=1;
    printf("p=%11d\n",p);
    p=p*n;
    return p;
    
}

实验2.2

#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;
    
}

实验3

#include <stdio.h>
long long func(int n); // 函数声明
int main() {
int n;
long long f;
while (scanf("%d", &n) != EOF) {
f = func(n); // 函数调用
printf("n = %d, f = %lld\n", n, f);
}
return 0;
}
long long func(int n){
    long long ans;
    if(n==0)ans=0;
//    else if(n==1)ans=1;
    else ans=2*func(n-1)+1;
    
    return ans;
}

实验4

#include <stdio.h>
int func(int n, int m);
int main() {
int n, m;
while(scanf("%d%d", &n, &m) != EOF)
printf("n = %d, m = %d, ans = %d\n", n, m, func(n, m));
return 0;
}
int func(int n,int m){
    int ans;
    if(m>n)ans=0;
    else if(m==n||m==0)ans=1;
    else if(m==1)ans=n;
    else ans=func(n-1,m)+func(n-1,m-1);
    return ans;
    
    
}

实验5

#include <stdio.h>
int mul(int n, int m);
int main() {
int n, m;
while(scanf("%d%d", &n, &m) != EOF)
printf("%d * %d = %d\n", n, m, mul(n, m));
return 0;
}
int mul(int n,int m){
    int t;
    if(n==0||m==0)return 0;
    if(n<m||n==m){t=n;n=m;m=t;
    return n+mul(n,m-1);
    
    }
    else return n+mul(n,m-1);
    
    
}

实验6
#include<stdio.h>
#include<stdlib.h>
void hanoi(unsigned int n,char from,char temp,char to);
void moveplate(unsigned int n,char from,char to);
int step(int n);
int main(){
    unsigned int n;
    while(scanf("%u",&n)!=EOF){
        hanoi(n,'A','B','C');
    printf("一共移动了%d次",step(n));
        
    }
    
    
    
    return 0;
}
void hanoi(unsigned int n,char from,char temp,char to){
    if(n==1)
    moveplate(n,from,to);
    else{
        hanoi(n-1,from,to,temp);
        moveplate(n,from,to);
        hanoi(n-1,temp,from,to);
        
    }
    
}
void moveplate(unsigned int n,char from,char to){
    printf("%u:%c-->%c\n",n,from,to);
    
}
int step(int n){
    if(n<=1)return 1;
    else return 2*step(n-1)+1;
    
    
}

实验7

#include <stdio.h>
int is_prime(int n);
int main()
{
    int num, f;
    int stop = 0;
    int i = 2;
    while (i < 20)
    {
        i =i+2;
        for (int j = 2; j < i; j++)
        {
            num = i - j;
            f = is_prime(num);
            if (f)
            {
                printf("%d = %d + %d\n", i, j, num);
                stop = 1;
            }
            if (stop) break;
        }
        stop = 0;
    }
 
    return 0;
}
int is_prime(int n)
{
    if (n == 1) return 0;

    for (int i = 2; i < n; i++)
    {
        int stop = 0;
        if (n % i == 0)
        {
            return 0;
            stop = 1;
        }
        if (n == 2 || (n % i != 0 && i == n - 1)) return 1;
        if (stop) break;
    }
}

实验8


#include <stdio.h>
#include<stdlib.h>
#include<math.h>
long fun(long s); // 函数声明
int main() {
long s, t;
printf("Enter a number: ");
while (scanf("%ld", &s) != EOF) {
t = fun(s); // 函数调用
printf("new number is: %ld\n\n", t);
printf("Enter a number: ");
}
return 0;
}
long fun(long s){
     int n;
    int i = 0;
    int count = 0;
    while (s!=0)
    {
        n = s % 10;
        if (n % 2 != 0)
        {
           i = n * pow(10, count) + i;
            count++;
        }
        s = s / 10;
    }
    return i;
    
}