实验三

试验任务一

#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <windows.h>
#define N 80
void printText(int line, int col, char text[]);     // 函数声明
void printSpaces(int n);           //函数声明
void printBlankLines(int n); // 函数声明
int main()
{
    int line, col, i;
    char text[N] = "hi, May~";
    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;
        col = rand() % 80;
        printText(line, col, text);
        Sleep(1000);     //暂停1000ms
    }
    return 0;
}

// 打印n个空格
void printSpaces(int n)
{
    int i;
    for (i = 1; i <= n; ++i)
        printf(" ");
}


// 打印n行空白行
void printBlankLines(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 printText(int line, int col, char text[])
{
    printBlankLines(line - 1); // 打印n-1行空行
    printSpaces(col - 1);
    printf("%s", text);
}

试验任务二

// 利用局部static变量的特性，计算阶乘
#include <stdio.h>
long long fac(int n); // 函数声明
int main()
{
    int i, n;
    printf("Enter n: ");
    scanf_s("%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;
}

// 练习：局部static变量特性
#include <stdio.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);
    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;
}

试验任务三

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

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

    while (scanf_s("%d", &n) != 0)
    {
        f = fun(n);
        printf("n=%d,f=%lld\n", n, f);
    }
    return 0;
}
long long fun (int n)
{
    int m, i, s = 1;
    for (i = 0; i < n;i++)
    {
        s = s * 2;
        m = s - 1;
    }
    return m;
    
}

试验任务四

#include<stdio.h>
void hanoi(unsigned int n, char from, char temp, char to);
void moveplate(unsigned int n, char from, char to);
int main()
{
    unsigned int n;
    
    while (scanf_s("%u", &n) != 0)
    {
        hanoi(n, 'A', 'B', 'C');
        printf("一共移动了%u次.", 2 ^ n - 1);
        printf("\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("第%u个盘子:%c-->%c\n", n, from, to);
    
    printf("\n");
}

试验任务五

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

实验任务六

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

int main()
{
    long s, t;
    printf("Enter a number: ");
    while (scanf_s("%ld", &s) != 0)
    {
        t = fun(s);
        printf("new number is:%ld\n\n", t);
        printf("Enter a number: ");
    }
    return 0;
}
long fun(long s)
{
    int m = 1, k, s0 = 0;
    while (s != 0)
    {
        k = s % 10;
        if (k % 2 == 1)
        {
            s0 = s0 + k * m;
            m = 10 * m;
        }
        s = s / 10;
    }
    return s0;
}