实验3

1.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,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);
}

实现的功能：随机分布“hi,April”

2.实验任务2

1）

#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! = %lld\n", i, fac(i));
    
    return 0;
}

long long fac(int n) {
    static long long p = 1;
    
    p = p * n;
    
      printf("p=%lld\n", p);

    return p;
} 

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;
}

static变量可使函数在每次调用时保持上一次的值不变。

3.实验任务3

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 sum = 1;

    for (int i = 1;i <= n;i++)
        sum = sum * 2;
        sum = sum - 1;
    
        return sum;
}

4.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 s;
    

    if (n < m)
        return 0;
    else
        if (n == 0 || m == 0 || n == m)
            return 1;
        else
            s = func(n - 1, m) + func(n - 1, m - 1);
            return s;

}

5.实验任务5

1）

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

int main()
{
    int x, y;
    double ans;

    while (scanf_s("%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)
{
    int t, i;

    if (y < 0)
        t = -y;
    else
        t = y;

    double sum = 1;
    for (i = 1;i <= t;i++)
        sum = sum * x;
    if (y > 0)
        return sum;
    else
        sum = 1 / sum;
        return sum;

}

2）

int main()
{
    int x, y;
    double ans;

    while (scanf_s("%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)
{
    int m, n;
    
    if (y == 0)
        return 1;
    
    if (y > 0)
        m=x * mypow(x, y - 1);
    return m;

    if (y < 0)
        n = 1/ x * mypow(x, y);
    return n;

}

6.实验任务6

#include<stdio.h>

void hanoi(int n, char A, char B, char C);
void move(int n,char x, char y);

int p;

int main()
{
    int n;

    while (scanf_s("%d", &n) != EOF)
{
        p = 0;
        hanoi(n, 'A', 'B', 'C');
        printf("一共移动了%d次",p);
}
    return 0;
}
void hanoi(int n, char A, char B, char C)
{
    if (n == 1)
        move(n,A, C);
    else
    {
        hanoi(n - 1, A, B, C);
        move(n,A, C);
        hanoi(n - 1, B, A, C);
    }
}

void move(int n, char x, char y)
{
    p++;
    printf("%d:%c --> %c\n", n, x, y);
}

7.实验任务7

#include<stdio.h>

int is_prime(int x);

int main()
{
    int i, n;

    while (scanf_s("%d", &n) != EOF)
    {
        for (i = 2;i <= n;i++)
        {
            if (!is_prime(i) || !is_prime(n - i))
                continue;
            printf("%d=%d+%d\n", n, i, n - i);
            break;
        }
    }
    return 0;
}

int is_prime(int x)
{
    int i;
    for (i = 2;i * i <= x;i++)
        if (x % i == 0)
            return 0;
    return 1;
}

8.实验任务8

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

int main()
{
    long s, t;

    printf("Enter a number:");
    while (scanf_s("%ld", &s) != EOF)
    {
        t = func(s);
        printf("new number is:%ld\n\n", t);
        printf("Enter a number:");
    }
    return 0;
}
long func(long s)
{
    long t = 0, t1 = 0;
    while (s > 0)
    {
        int m = s % 10;
        s = s / 10;
        if (m % 2 == 1)
            t1 = t1 * 10 + m;
    }
    while (t1 > 0)
    {
        t = t * 10 + (t1 % 10);
        t1 = t1 / 10;
    }
    return t;
}