linux c++ uint8_t转string
时间: 2023-10-21 12:25:00 浏览: 77
要将 `uint8_t` 类型的变量转换为字符串,可以使用标准库中的 `sprintf` 函数。以下是一个示例代码,演示如何将 `uint8_t` 转换为字符串:
```c
#include <stdio.h>
#include <stdint.h>
int main() {
uint8_t num = 123;
char str[4];
sprintf(str, "%hhu", num);
printf("String representation: %s\n", str);
return 0;
}
```
在上面的代码中,我们使用 `%hhu` 格式说明符来将 `num` 变量转换为字符串。这个格式说明符用于无符号字符类型 `uint8_t`。转换后的字符串将存储在字符数组 `str` 中。
请注意,`sprintf` 函数用于将格式化的输出存储到字符串中。在这个例子中,我们将输出存储在 `str` 中。然后,我们使用 `printf` 函数打印出转换后的字符串。
运行上述代码将输出:
```
String representation: 123
```
这样,你就成功地将 `uint8_t` 类型的变量转换为字符串了。
相关问题
Linuxc++socket 接收protobuf并解码的demo,消息头定义了消息类型,消息长度,C++定义如下: #include<stdint.h> #pragma pack(push,1) enum FiuType { FIU_Heartbeat = 0, FIU_InstrumentDefine = 1, FIU_Snap = 2, FIU 金融数据服务 20 FIU_Order = 3, FIU_Trade = 4, FIU_Equilibrium = 5, FIU_CODE_END = 6, FOU_MAX }; struct FiuHeader { FiuHeader() { memset(this, 0, sizeof(*this)); usLen = sizeof(*this); } uint16_t usLen; uint8_t cType; }; #pragma pack(pop)
以下是一个简单的示例代码,演示如何在 Linux C++ Socket 中接收 Protobuf 并解码,前提是你已经将 Protobuf 安装在了你的系统上。
```
#include <iostream>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <string.h>
#include <google/protobuf/message.h>
#include "header.pb.h"
using namespace std;
int main() {
// 创建一个 TCP Socket
int sockfd = socket(AF_INET, SOCK_STREAM, 0);
if (sockfd == -1) {
cerr << "Failed to create socket!" << endl;
return -1;
}
// 设定服务器的 IP 地址和端口号
struct sockaddr_in serverAddr;
serverAddr.sin_family = AF_INET;
serverAddr.sin_port = htons(8000);
serverAddr.sin_addr.s_addr = inet_addr("127.0.0.1");
// 连接服务器
int ret = connect(sockfd, (struct sockaddr*)&serverAddr, sizeof(serverAddr));
if (ret == -1) {
cerr << "Failed to connect to server!" << endl;
close(sockfd);
return -1;
}
// 接收消息头
FiuHeader header;
int n = recv(sockfd, &header, sizeof(header), 0);
if (n != sizeof(header)) {
cerr << "Failed to receive message header!" << endl;
close(sockfd);
return -1;
}
// 根据消息类型解码 Protobuf 消息
google::protobuf::Message* message = nullptr;
switch (header.cType) {
case FIU_Heartbeat:
message = new Heartbeat;
break;
case FIU_InstrumentDefine:
message = new InstrumentDefine;
break;
case FIU_Snap:
message = new Snap;
break;
case FIU_Order:
message = new Order;
break;
case FIU_Trade:
message = new Trade;
break;
case FIU_Equilibrium:
message = new Equilibrium;
break;
case FIU_CODE_END:
default:
cerr << "Invalid message type!" << endl;
close(sockfd);
return -1;
}
// 接收 Protobuf 消息
n = recv(sockfd, message, header.usLen - sizeof(header), 0);
if (n != header.usLen - sizeof(header)) {
cerr << "Failed to receive Protobuf message!" << endl;
close(sockfd);
return -1;
}
// 打印 Protobuf 消息
cout << "Received message: " << endl;
cout << message->DebugString() << endl;
// 关闭 Socket
close(sockfd);
return 0;
}
```
在此示例代码中,我们通过 Socket 接收消息头(即结构体 FiuHeader),然后根据消息类型(即结构体 FiuHeader 中的字段 cType)创建相应的 Protobuf 消息对象,并通过 Socket 接收 Protobuf 消息。最后,我们将接收到的 Protobuf 消息打印出来。请注意,此示例代码仅适用于仅包含一个 Protobuf 消息的情况,如果你的消息中包含多个 Protobuf 消息,你可能需要更复杂的逻辑来处理。
Linux C++ 发送DHCP报文获取DHCP信息
要发送DHCP报文获取DHCP信息,可以使用Linux下的socket编程来实现。具体步骤如下:
1. 创建socket对象,使用raw socket类型。
2. 设置socket属性,包括IP地址、端口号等。
3. 创建DHCP报文,并填充报文字段。
4. 发送DHCP报文。
5. 接收DHCP服务器的响应报文。
6. 解析响应报文,获取DHCP信息。
以下是一个简单的示例代码:
```c++
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#define BUF_SIZE 1024
#define DHCP_PORT 67
#define DHCP_SERVER_PORT 68
typedef struct {
uint8_t op; // Message op code / message type.
uint8_t htype; // Hardware address type (e.g., '1' = 10mb ethernet).
uint8_t hlen; // Hardware address length (e.g., '6' for 10mb ethernet).
uint8_t hops; // Client sets to zero, optionally used by relay agents when booting via a relay agent.
uint32_t xid; // Transaction ID, a random number chosen by the client, used by the client and server to associate messages and responses between a client and a server.
uint16_t secs; // Filled in by client, seconds elapsed since client began address acquisition or renewal process.
uint16_t flags; // Broadcast flag.
struct in_addr ciaddr; // Client IP address; only filled in if client is in BOUND, RENEW or REBINDING state and can respond to ARP requests.
struct in_addr yiaddr; // 'your' (client) IP address.
struct in_addr siaddr; // IP address of next server to use in bootstrap; returned in DHCPOFFER, DHCPACK by server.
struct in_addr giaddr; // Relay agent IP address, used in booting via a relay agent.
uint8_t chaddr[16]; // Client hardware address.
char sname[64]; // Optional server host name, null terminated string.
char file[128]; // Boot file name, null terminated string; "generic" name or null in DHCPDISCOVER, fully qualified directory-path name in DHCPOFFER.
uint32_t magic_cookie; // Fixed value: 0x63825363.
uint8_t options[308]; // Optional parameters field.
} dhcp_packet;
int main(int argc, char* argv[]) {
int sockfd;
struct sockaddr_in servaddr, cliaddr;
char buf[BUF_SIZE];
socklen_t len = sizeof(cliaddr);
dhcp_packet packet;
// 创建socket对象
sockfd = socket(AF_INET, SOCK_RAW, IPPROTO_UDP);
if (sockfd < 0) {
perror("socket");
exit(1);
}
// 设置socket属性
memset(&servaddr, 0, sizeof(servaddr));
servaddr.sin_family = AF_INET;
servaddr.sin_port = htons(DHCP_SERVER_PORT);
servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
if (bind(sockfd, (struct sockaddr*)&servaddr, sizeof(servaddr)) < 0) {
perror("bind");
exit(1);
}
// 创建DHCP报文
memset(&packet, 0, sizeof(packet));
packet.op = 0x01; // Message type: Boot Request
packet.htype = 0x01; // Hardware type: Ethernet
packet.hlen = 0x06; // Hardware address length: 6
packet.xid = random(); // Transaction ID
packet.magic_cookie = htonl(0x63825363); // DHCP Magic Cookie
// DHCP Option 53: DHCP Discover
packet.options[0] = 0x35; // Option 53
packet.options[1] = 0x01; // Length
packet.options[2] = 0x01; // DHCP Discover
// DHCP Option 55: Parameter Request List
packet.options[3] = 0x37; // Option 55
packet.options[4] = 0x04; // Length
packet.options[5] = 0x01; // Subnet Mask
packet.options[6] = 0x03; // Router
packet.options[7] = 0x06; // Domain Name Server
packet.options[8] = 0x0f; // Domain Name
packet.options[9] = 0x2c; // Static Route
packet.options[10] = 0xff; // End
// 发送DHCP报文
memset(&cliaddr, 0, sizeof(cliaddr));
cliaddr.sin_family = AF_INET;
cliaddr.sin_port = htons(DHCP_PORT);
cliaddr.sin_addr.s_addr = inet_addr("255.255.255.255");
if (sendto(sockfd, &packet, sizeof(packet), 0, (struct sockaddr*)&cliaddr, sizeof(cliaddr)) < 0) {
perror("sendto");
exit(1);
}
// 接收DHCP服务器的响应报文
memset(buf, 0, sizeof(buf));
if (recvfrom(sockfd, buf, sizeof(buf), 0, (struct sockaddr*)&cliaddr, &len) < 0) {
perror("recvfrom");
exit(1);
}
// 解析响应报文,获取DHCP信息
// ...
close(sockfd);
return 0;
}
```