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[]);
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);
}

在任意行任意列输出hi, November~

实验任务2

#include<stdio.h>
long long fac(int n);
int main()
{
    int i, n;
    printf("Enter n:");
    scanf_s("%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;
}

#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;
}

static变量再一次被使用时会保留上一次的值

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);
    }
    return 0;
}
long long func(int n)
{
    long long a;
    if (n==1)
        return 1;
    a=2*func(n - 1)+1;
    return a;
}

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));
    return 0;
}
int func(int n, int m)
{
    int a;
    if (n < m)
        return 0;
    else if (m == 0)
        return 1;
    a = func(n - 1, m) + func(n - 1, m - 1);
    return a;
}

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;
}
int mul(int n, int m)
{
    int t,a;
    if (m > n)
    {
        t = m; m = n; n = t;
    }
    if(m == 0)
        return 0;
    if (m == 1)
        return n;
    a = n + mul(n, m - 1);
    return a;
}

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;
int main()
{
    unsigned int n; 
    while (scanf_s("%u", &n) != EOF)
    {
        count = 0;
        hanoi(n, 'A', 'B', 'C');
        printf("一共移动了%d次\n", count);
    }
    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)
{
    count += 1;
    printf("%u: %c-->%c\n", n, from, to);
}

实验任务7

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

实验任务8

#include <stdio.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;
}
long fun(long s)
{
    int m=1,sum=0;
    while (s != 0)
    {
        if ((s%10) % 2 == 1)
        {
            sum += (s%10)* m;
            m=m * 10;
        }
        s=s / 10;
    }
    return sum;
}