东风草堂博客

#include <iostream>

// 上下文类，包含了促销活动的信息
class Context {
public:
    double totalPrice;
    // 其他上下文信息...
};

// 抽象基类，具体的活动需要实现这个基类
class ProStrategy {
public:
    virtual double CalcPro(const Context& ctx) = 0;
    virtual ~ProStrategy() {}
};

// 具体促销活动1
class DiscountStrategy : public ProStrategy {
public:
    double CalcPro(const Context& ctx) override {
        // 实际的促销计算逻辑，这里简化为打八折
        return ctx.totalPrice * 0.8;
    }
};

// 具体促销活动2
class CashBackStrategy : public ProStrategy {
public:
    double CalcPro(const Context& ctx) override {
        // 实际的促销计算逻辑，这里简化为满100返20
        return ctx.totalPrice >= 100 ? ctx.totalPrice - 20 : ctx.totalPrice;
    }
};

// 促销活动的上下文类
class Promotion {
public:
    Promotion(ProStrategy* strategy = nullptr) : strategy(strategy) {}

    // 设置促销策略
    void SetStrategy(ProStrategy* strategy) {
        this->strategy = strategy;
    }

    // 计算促销价格
    double CalculatePromotion(const Context& ctx) {
        if (strategy) {
            return strategy->CalcPro(ctx);
        }
        return ctx.totalPrice;
    }

private:
    ProStrategy* strategy;
};

int main() {
    Context context;
    context.totalPrice = 120;

    // 创建促销活动上下文
    Promotion promotion;

    // 选择具体促销策略1（打八折）
    promotion.SetStrategy(new DiscountStrategy());
    double discountedPrice = promotion.CalculatePromotion(context);
    std::cout << "Discounted Price: " << discountedPrice << std::endl;

    // 选择具体促销策略2（满100返20）
    promotion.SetStrategy(new CashBackStrategy());
    double cashBackPrice = promotion.CalculatePromotion(context);
    std::cout << "Cash Back Price: " << cashBackPrice << std::endl;

    return 0;
}

#include <iostream>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <string.h>
#include <stdio.h>

int main(void)
{
  int fd = socket(PF_INET, SOCK_STREAM, 0);
  if (fd == -1) {
    printf("create socket error %d\n", errno);
    exit(1);
  }
  int on = 1;
  setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on));
  struct sockaddr_in addr;
  addr.sin_family = PF_INET;
  addr.sin_port = htons(8081);
  addr.sin_addr.s_addr = htonl(INADDR_ANY);
  if (bind(fd, reinterpret_cast<struct sockaddr *>(&addr),
    sizeof(addr)) != 0) {
    printf("bind socket error %d\n", errno);
    switch (errno)
    {
      case EADDRINUSE:
        std::cout << "Address already in use" << std::endl;
        break;

      default:
        break;
    }
    close(fd);
    exit(1);
  }
  if (listen(fd, 1024) != 0) {
    printf("listen socket error %d\n", errno);
    close(fd);
    exit(1);
  }
  while(1) {
    struct sockaddr_in cli;
    int len = sizeof(cli);
    int nfd = accept(fd, reinterpret_cast<struct sockaddr *>(&cli),
      reinterpret_cast<socklen_t *>(&len));
    if(nfd == -1) {
      printf("accept socket error %d\n", errno);
      close(fd);
      exit(1);
    }

    char buf[1024];
    char content[] = "hello http!";
    bzero(buf, 1024);
    recv(nfd, buf, 1024, 0);
    printf("----------------recv msg----------------\n%s\n", buf);
    bzero(buf, 1024);
    sprintf(buf, "HTTP/1.1 200 OK\r\nContent-Length: %d\r\n"
      "Content-Type: text/html\r\n\r\n%s", static_cast<int>(strlen(content)), content);
    printf("----------------ready to send buf----------------\n%s\n", buf);
    if (send(nfd, buf, strlen(buf), 0) == -1) {
      printf("write socket error %d\n", errno);
    }
    if (close(nfd) != 0)
      printf("close nfd err: %d\n", errno);
  }

  if (close(fd) != 0)
    printf("close fd err: %d\n", errno);
  exit(0);
}

// socket create and verification 
sockfd = socket(AF_INET, SOCK_STREAM, 0); 
if (sockfd == -1) { 
    printf("socket creation failed...\n"); 
    exit(0); 
} 
else
    printf("Socket successfully created..\n");