在C++中，要實現ICMP協議，通常需要使用原始套接字（raw sockets）來發送和接收ICMP數據包

#include<iostream>
#include <cstring>
#include <unistd.h>
#include <netinet/ip.h>
#include <netinet/ip_icmp.h>
#include <arpa/inet.h>
#include <sys/socket.h>
#include <sys/types.h>

const int ICMP_PACKET_SIZE = 64;

// 構建ICMP請求數據包
void build_icmp_packet(char *buffer, int &length) {
    icmphdr *icmp = (icmphdr *) buffer;
    
    // 設置ICMP類型為回顯請求
    icmp->type = ICMP_ECHO;
    icmp->code = 0;
    icmp->checksum = 0;
    icmp->un.echo.id = htons(getpid());
    icmp->un.echo.sequence = htons(1);

    // 計算校驗和
    int checksum = 0;
    for (int i = 0; i< length / 2; ++i) {
        checksum += ((unsigned short *) buffer)[i];
    }
    while (checksum >> 16) {
        checksum = (checksum & 0xffff) + (checksum >> 16);
    }
    icmp->checksum = ~checksum;
}

int main() {
    int sockfd;
    struct sockaddr_in dest_addr;
    char buffer[ICMP_PACKET_SIZE];
    int length = ICMP_PACKET_SIZE;

    // 創建原始套接字
    if ((sockfd = socket(AF_INET, SOCK_RAW, IPPROTO_ICMP)) < 0) {
        std::cerr << "Failed to create raw socket"<< std::endl;
        return -1;
    }

    // 設置目標地址
    dest_addr.sin_family = AF_INET;
    dest_addr.sin_addr.s_addr = inet_addr("8.8.8.8");

    // 構建ICMP請求數據包
    build_icmp_packet(buffer, length);

    // 發送ICMP請求數據包
    if (sendto(sockfd, buffer, length, 0, (struct sockaddr *) &dest_addr, sizeof(dest_addr)) < 0) {
        std::cerr << "Failed to send ICMP packet"<< std::endl;
        close(sockfd);
        return -1;
    }

    // 接收ICMP響應數據包
    socklen_t addr_len = sizeof(dest_addr);
    if (recvfrom(sockfd, buffer, length, 0, (struct sockaddr *) &dest_addr, &addr_len) < 0) {
        std::cerr << "Failed to receive ICMP packet"<< std::endl;
        close(sockfd);
        return -1;
    }

    // 處理ICMP響應數據包
    icmphdr *icmp = (icmphdr *) buffer;
    if (icmp->type == ICMP_ECHOREPLY) {
        std::cout << "Received ICMP echo reply from " << inet_ntoa(dest_addr.sin_addr)<< std::endl;
    } else {
        std::cerr << "Received unexpected ICMP packet type: " << icmp->type<< std::endl;
    }

    // 關閉套接字
    close(sockfd);

    return 0;
}

這個示例程序首先創建一個原始套接字，然后構建一個ICMP回顯請求數據包，并將其發送到指定的目標地址。接著，程序等待接收ICMP響應數據包，并檢查其類型是否為回顯響應。如果是，則輸出相應的信息；否則，輸出錯誤信息。最后，關閉套接字。

注意：運行此程序可能需要root權限，因為原始套接字需要特殊權限。在Linux系統上，可以使用sudo命令運行程序。