实验3

实验任务1

#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <windows.h>
#define N 80
void print_text(int line, int col, char text[]); // 函数声明
void print_spaces(int n); // 函数声明
void print_blank_lines(int n); // 函数声明
int main() {
    int line, col, i;
    char text[N] = "hi, November~";
    srand(time(0)); // 以当前系统时间作为随机种子
    for (i = 1; i <= 10; ++i) {
        line = rand() % 25;  //产生0-24之间的随机整数，即小黑屏有25行
        col = rand() % 80;   //产生0-79之间的随机整数，即小黑屏有80列
        print_text(line, col, text);
        Sleep(1000); // 暂停1000ms
    }
    return 0;
}
// 打印n个空格
void print_spaces(int n) {
    int i;
    for (i = 1; i <= n; ++i)
        printf(" ");
}
// 打印n行空白行
void print_blank_lines(int n) 
{
    int i;
    for (i = 1; i <= n; ++i)
        printf("\n");
}
// 在第line行第col列打印一段文本
void print_text(int line, int col, char text[]) {
    print_blank_lines(line - 1); // 打印(line-1)行空行
    print_spaces(col - 1); // 打印(col-1)列空格
    printf("%s", text); // 在第line行、col列输出text中字符串
}

程序功能：在屏幕上打印出动画的"hi,November"

实验任务2

2.1c

#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));
    }
    system("pause");
    return 0;
}
//函数定义
long long fac(int n){
    static long long p=1;
    p=p*n;
    return p;
}

2.2c

#include<stdio.h>
int func(int,int);

int main(){
    int k=4,m=1,p1,p2;

    p1=func(k,m);
    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;
}

static变量具有继承性，即只赋初值一次，以后每次调用函数时不再重新赋初值而保留上次函数结束时的值

实验任务3

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

int main(){
    int n;
    long long f;

    while (scanf_s("%d",&n)!=EOF){
        f=func(n);
        printf("n=%d,f=%lld\n",n,f);
    }
    system("pause");
    return 0;
}
    //函数定义
    long long func(int n){
        int s;
            if (n==0)
                return 0;
            else if(n!=0)
                return 2*func(n-1)+1;
        }
            

实验任务4

#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));
    system("pause");
    return 0;
}
//函数定义
int func(int n,int m){
    int s;
    if(n<m){
        return 0;
    }
    if(n==m||m==0||n==1){
        return 1;
    }
    else {
        return func(n-1,m)+func(n-1,m-1);
    }
}

实验任务5

#include<stdio.h>
int mul(int n,int m);

int main(){
    int n,m;
    while(scanf_s("%d%d",&n,&m)!=EOF)
        printf("%d*%d=%d\n",n,m,mul(n,m));
    return 0;
}
//函数定义
int mul(int n,int m){
    int i=1;
    int s=0;
    if(n==0||m==0){
        return 0;
    }
    else{
    for(i=1;i<=m;++i){
        s+=n;
    }
    return s;
    }
    }

实验任务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 count=0;
int main()
{
    unsigned int n;
    while(scanf_s("%u",&n)!=EOF){
    hanoi(n,'A','B','C');
    printf("一共移了%d次\n",count);
    count=0;
    }
    system("pause");
    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);
    count++;
}

实验任务7

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

实验任务8

#include<stdio.h>
#include<math.h>
long fun(long s);

int main(){

    long s,t;

    printf("Enter a number:");
    while(scanf_s("%ld",&s)!=EOF){
        t=fun(s);
        printf("new number is:%ld\n\n",t);
        printf("Enter a number: ");
    }
    return 0;
}
//函数声明
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;
}