实验四

#include <stdio.h>
long long fun(int n);   // 函数声明 

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

    while (scanf_s("%d", &n) != EOF) {
        f = fun(n);  // 函数调用 
        printf("n = %d, f = %lld\n", n, f);
    }

    return 0;
}

// 函数定义
// 补足。。。 
long long b(int n)
{
    if (n > 1)
        return 2 * b(n - 1);
    else
        return 2;
}

long long fun(int n)
{
    long long a;
    if (n > 1)
        return fun(n - 1) + b(n - 1);
    else
        return 1;
}

 

long fac(int n);

int main() {
    int i, n;

    printf("En#include<stdio.h>
longter 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;

    return p;
}

#include<stdio.h>
#define N 1000

int fun(int n, int m, int bb[N]) {
    int i, j, k = 0, flag;

    for (j = n; j <= m; j++) {
        flag = 1;
        for (i = 2; i < j; i++)
            if (j % i == 0) {
                flag = 0;
                break;
            }
        if (flag == 1)
            bb[k++] = j;
    }
    return k;
}

int main() {
    int n = 0, m = 0, i, k, bb[N];

    while (scanf_s("%d %d", &n, &m) != EOF) {



        for (i = 0; i < m - n; i++)
            bb[i] = 0;

        k = fun(n, m, bb);

        for (i = 0; i < k; i++)
            printf("%4d", bb[i]);
        printf("\n");
    }

    return 0;
}

#include <stdio.h>
void dec2n(int x, int n);

int main() {
    int x;

    printf("输入一个十进制整数: ");
    scanf_s("%d", &x);

    dec2n(x, 2);
    dec2n(x, 8);
    dec2n(x, 16);
    return 0;
}

void dec2n(int x, int n) {
    int i, a, N;
    char b[100];

    for (i = 0; x != 0; i++) {
        b[i] = x % n;
        x = x / n;
    }
    if (b[i] > 9)
        switch (b[i])
        {
        case 10:b[i] = 'A'; break;
        case 11:b[i] = 'B'; break;
        case 12:b[i] = 'C'; break;
        case 13:b[i] = 'D'; break;
        case 14:b[i] = 'E'; break;
        case 15:b[i] = 'F'; break;
        }