C语言函数大全--h开头的函数

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

int main(void)
{
   double result, x = 3.0, y = 4.0;
   result = hypot(x, y);

   float resultf, xf = 3.0, yf = 4.0;
   resultf = hypotf(xf, yf);

   long double resultL, xL = 3.0, yL = 4.0;
   resultL = hypotl(xL, yL);

   printf("The hypotenuse of a right triangle whose legs are %lf and %lf is %lf\n", x, y, result);
   printf("The hypotenuse of a right triangle whose legs are %f and %f is %f\n", xf, yf, resultf);
   printf("The hypotenuse of a right triangle whose legs are %Lf and %Lf is %Lf\n", xL, yL, resultL);

   return 0;
}

#include<stdio.h>
#include<math.h>
int main()
{
    double result = 1.0/0.0;
    printf("1.0/0.0 = %lf\n", result);
    if (result == HUGE_VAL)
        puts("1.0/0.0 == HUGE_VAL\n");

    float resultf = 1.0f/0.0f;
    printf("1.0f/0.0f = %f\n", resultf);
    if (resultf == HUGE_VALF)
        puts("1.0f/0.0f == HUGE_VALF\n");

    long double resultL = 1.0L/0.0L;
    printf("1.0L/0.0L = %Lf\n", resultL);
    if (resultL == HUGE_VALL)
        puts("1.0L/0.0L == HUGE_VALL\n");

    return 0;  
}

#include <stdio.h>
#include <conio.h>
#include <dos.h>
#define IGNORE  0
#define RETRY   1
#define ABORT   2
int buf[500];

//定义捕获磁盘问题的错误消息
static char *err_msg[] = {
    "write protect",
    "unknown unit",
    "drive not ready",
    "unknown command",
    "data error (CRC)",
    "bad request",
    "seek error",
    "unknown media type",
    "sector not found",
    "printer out of paper",
    "write fault",
    "read fault",
    "general failure",
    "reserved",
    "reserved",
    "invalid disk change"
};

int error_win(char *msg)
{
    int retval;
    cputs(msg);

    // 提示用户按键中止、重试、忽略
    while(1)
    {
        retval= getch();
        if (retval == 'a' || retval == 'A')
        {
            retval = ABORT;
            break;
        }
        if (retval == 'r' || retval == 'R')
        {
            retval = RETRY;
            break;
        }
        if (retval == 'i' || retval == 'I')
        {
            retval = IGNORE;
            break;
        }
    }

    return(retval);
}

/*
    pragma warn-par 减少了由于处理程序未使用参数errval、bp 和 si而产生的警告。
*/
#pragma warn -par

int handler(int errval,int ax,int bp,int si)
{
    static char msg[80];
    unsigned di;
    int drive;
    int errorno;
    di= _DI;

    // 如果这不是磁盘错误，那么是另一个设备出现故障
    if (ax < 0)
    {
        error_win("Device error");
        // 返回到直接请求中止的程序
        hardretn(ABORT);
    }
    // 否则就是磁盘错误
    drive = ax & 0x00FF;
    errorno = di & 0x00FF;
    sprintf(msg, "Error: %s on drive %c\r\nA)bort, R)etry, I)gnore: ", err_msg[errorno], 'A' + drive);
    // 通过dos中断0x23返回程序，并由用户输入中止、重试或忽略。
    hardresume(error_win(msg));
    return ABORT;
}

#pragma warn +par

int main(void)
{
    // 在硬件问题中断上安装我们的处理程序
    harderr(handler);
    clrscr();
    printf("Make sure there is no disk in drive A:\n");
    printf("Press any key ....\n");
    getch();
    printf("Trying to access drive A:\n");
    printf("fopen returned %p\n", fopen("A:temp.dat", "w"));
    return 0;
}

#include <stdio.h>
#include <conio.h>

int main(void)
{
    clrscr();

    lowvideo();
    cprintf("Low Intensity text\r\n");
    highvideo();
    gotoxy(1,2);
    cprintf("High Intensity Text\r\n");

    return 0;
}

#include <stdio.h>
#include <stdlib.h>
#include <search.h>

char *data[] = { "alpha", "bravo", "charlie", "delta",
     "echo", "foxtrot", "golf", "hotel", "india", "juliet",
     "kilo", "lima", "mike", "november", "oscar", "papa",
     "quebec", "romeo", "sierra", "tango", "uniform",
     "victor", "whisky", "x-ray", "yankee", "zulu"
};

int main(void)
{
    ENTRY e, *ep;
    int i;

    hcreate(30);

    for (i = 0; i < 24; i++) {
        e.key = data[i];
        // 数据只是一个整数，而不是指向某个东西的指针
        e.data = (void *) i;
        ep = hsearch(e, ENTER);
        // 这里不应该有失败场景
        if (ep == NULL) {
            fprintf(stderr, "entry failed\n");
            exit(EXIT_FAILURE);
        }
    }

    for (i = 22; i < 26; i++) {
        // 从表中打印两个条目，并显示其中两个不在表中
        e.key = data[i];
        ep = hsearch(e, FIND);
        printf("%9.9s -> %9.9s:%d\n", e.key, ep ? ep->key : "NULL", ep ? (int)(ep->data) : 0);
    }
    hdestroy();
    exit(EXIT_SUCCESS);
}

#include <stdio.h>
#include <stdint.h>     // 提供 uint16_t, uint32_t 类型
#include <arpa/inet.h>  // Linux/macOS 头文件（网络字节序转换）

int main() {
    // 示例1：转换16位端口号（host to network short）
    uint16_t host_port = 0x1234;  // 主机字节序的端口（假设是小端模式）
    uint16_t net_port = htons(host_port);
    printf("主机端口: 0x%04x -> 网络端口: 0x%04x\n", host_port, net_port);

    // 示例2：转换32位IP地址（host to network long）
    uint32_t host_ip = 0x12345678;  // 主机字节序的IP地址
    uint32_t net_ip = htonl(host_ip);
    printf("主机IP: 0x%08x -> 网络IP: 0x%08x\n", host_ip, net_ip);

    return 0;
}