实验3

1

2

3

#include <stdio.h>
#include<math.h>
long long func(int n);
int main() {
    int n;
    long long f;
    printf("输入一个整数：");
    while (scanf_s("%d", &n) != EOF) {
        f = func(n);
        printf("n = %d, f = %lld\n", n, f);
    }
    return 0;
}
long long func(int n)
{
    if (n == 1)
        return 1;
    else
        return 2 * func(n - 1) + 1;
}

 

 4

#include <stdio.h>
int func(int n, int m);
int main() {
    int n, m;
    printf("请输入整数m，n：");
    while (scanf_s("%d%d", &n, &m) != EOF)
        printf("n = %d, m = %d, C%d%d = %d\n", n, m,n,m, func(n, m));
    return 0;
}
int func(int n, int m)
{
    int t;

    if (n < m)
        
        return 0;

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

5

#include <stdio.h>
int mul(int n, int m);
int main() {
    int n, m;
    printf("请输入两个整数：");
    while (scanf_s("%d%d", &n, &m) != EOF)
        printf("%d X %d = %d\n", n, m, mul(n, m));
    return 0;
}
int mul(int n, int m)
{
    int t;
    if (n == 0 || m == 0)
        return 0;
    if (n == 1)
        return m;
    if (m == 1)
        return n;
    else
    {
        t = mul(n - 1, m) + m;
        return t;
    }

}

 6

7

8

#include <stdio.h>
#include <math.h>

long fun(long s);

int main() {
    long s, t;

    printf("输入一个整数: ");

    while (scanf_s("%ld", &s) != EOF)
    {
        t = fun(s);
        printf("新的数为: %ld\n\n", t);
        printf("输入一个整数: ");
    }

    return 0;
}

long fun(long s)
{
    int n;
    int num = 0;
    int count = 0;
    while (s != 0)
    {
        n = s % 10;
        if (n % 2 != 0)
        {
            num = pow(10, count) * n + num;
            count++;
        }
        s /= 10;
    }
    return num;
}