实验3

task 1

程序源码：

#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, April~";
    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);

}

程序运行截图：

结论： 代码实现了随机生成几个hi April~

task2-1

程序源码：

#include<stdio.h>
#include <stdlib.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));
    system("pause");
    return 0;
}
 long long fac(int n){
     static long long p = 1;
     p = p * n;
     return p;
 }

程序运行截图

task 2-1.1

程序源码：

#include<stdio.h>
#include <stdlib.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));
    system("pause");
    return 0;
}
 long long fac(int n){
     static long long p = 1;
     printf("p = %lld\n",p);
     p = p * n;
     return p;
 }

程序运行截图：

task2-2

程序源码：

#include <stdio.h>
#include<stdlib.h>
int func(int, int); // 函数声明
int main() {
int k = 4, m = 1, p1, p2;
p1 = func(k, m); // 函数调用
p2 = func(k, m); // 函数调用
printf("%d, %d\n", p1, p2);
 system("pause");
return 0;
}
// 函数定义
int func(int a, int b) {
static int m = 0, i = 2;
i += m + 1;
m = i + a + b;

return m;
}

程序运行截图：

实验结论:static的作用是使用时保留函数调用后的数值并在下一个函数调用的时候使用

task-3

程序源码：

#include<stdio.h>
#include<stdlib.h>
long long func(int n);
int main(){
    int n;
    long long f;

   while (scanf("%d", &n) !=EOF){
       f = func(n);
       printf("n = %d, f = %lld\n", n,f);
   }
   system("pause");
   return 0;
}
long long func(int n){
    long long f=1;
     
    int i;
    for( i = 1;i<=n;i++)
        f = 2*f;
         
    f = f-1;
 
    return f;
}

程序运行截图

task-4

程序源码：

#include <stdio.h>
int func(int n, int m);
int main() {
    int n, m;
    while (scanf_s("%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 (n < m)
        return 0;
    else if (n == m || m == 0)
        return 1;
    else {
        return  func(n - 1, m - 1) + func(n-1, m );
        
    }


}

程序运行截图：

task5

程序源码：

#include<stdio.h>
double mypow(int x, int y);

int main(){
    int x, y;
    double ans;
    
    while(scanf("%d%d", &x, &y) != EOF){
        ans = mypow(x, y);
        printf("%d的%d次方： %g\n\n", x, y, ans);
        
    }
    return 0;
} 

double mypow(int x, int y){
    double ans=1.0;
    if(y>=0)
    {for(int i = 1;i<=y;i++){
        ans = ans*x;
    } }
    else{
        for(int i = 1;i<=-y;i++){
            ans = ans/x; 
        }
    }
    return ans;
    }

程序运行截图：

5-2

程序源码：

#include<stdio.h>
double mypow(int x, int y);

int main(){
    int x, y;
    double ans;
    
    while(scanf("%d%d", &x, &y) != EOF){
        ans = mypow(x, y);
        printf("%d的%d次方： %g\n\n", x, y, ans);
        
    }
    return 0;
} 

double mypow(int x, int y){
    if(y == 0)
    return 1.0;
    if(y<0)
    return 1.0/mypow(x,-y);
    if(y>0) 
    return 1.0*x*mypow(x,y-1);
}

程序运行截图：

task-6

程序源码：

#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 ans;

int main()
{
    unsigned int n;

    while(scanf("%u", &n)!=EOF) {
    ans = 0;
    hanoi(n, 'A','B','C');
    printf("一共输入了%d次\n",ans);
    }
    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){
 
     ans++;
     printf("%u:%c-->%c\n",n,from,to);
 }

程序运行截图：

task-7

程序源码：

#include<stdio.h>
int is_prime(int n);
int main(){
int n, m;
    for(n = 4;n<=20;n=n+2)
      for(m = 2;m<=20;m++)
       {
          if(is_prime(m)==1&&is_prime(n-m)==1)
          {
           printf("%d = %d + %d\n",n,m,n-m); break;
           }
           else 
           continue; 
        }
    
return 0;    
}
int is_prime(int n)
{

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

}

程序运行截图：

task-8

程序源码：

#include <stdio.h>
#include<stdlib.h>
#include <math.h>
long func(long s);
int main(){
    long s,t;
    printf("Enter a number:");
    while(scanf("%ld",&s)!=EOF){
        t=func(s);
        printf("new number is:%ld\n\n",t);
        printf("Enter a number:");
    }
    system("pause");
    return 0;
}
long func(long s)
{
    int t, num=0, i=0;
    while(s!=0)
    {
        t=s%10;
        if(t%2==1){
            num=num+t * pow(10, i);
            i++;
        }
        s=s/10;
    }
    return num;
}

程序运行截图：