pb 字符串不为空

PB（Protocol Buffers）是一种Google开发的结构化数据序列化格式，它允许你在多种语言之间高效地进行数据交换。当提到"pb字符串不为空"，通常是指在处理Protocol Buffers消息时，检查某个字段是否已经设置并且不是空值。

在使用protobuf时，如果你有一个字符串类型的变量或字段，你可以通过`has_string_field`方法检查该字段是否存在，然后通过`string_field`获取其值。如果`has_string_field`返回true，并且`string_field`不是空字符串（通常是长度大于0），那么就可以认为该字符串不为空。

例如，在Python的protobuf库中，可能会这样操作：

if message.has_string_field and message.string_field != "":
    print(f"The string field is not empty: {message.string_field}")
else:
    print("String field is either missing or empty.")

相关问题

条件1.使用stm32f103c8t6,c语言编程条件2.使用PA1,PA2,PA3,PA4,PA5，PA6配置成上拉输入,根据6个引脚的电平高低生成。例如000000表示6引脚电平全为0,并使用串口1以字符串形式发送该二进制数到PC端。统计该二进制数中0的次数记作zeo_count;条件3.串口1使用中断接收数据,结束符0X0D,0X0A.条件4.条件2中的zeo_count与下一次条件2中的zeo_count比较,若前一次zeo_count大于后一次zeo_count;则打开蜂鸣器条件5.若串口接收字符串为"1",关闭蜂鸣器; 若串口接收字符串为"2",打开蜂鸣器;若串口接收字符串为"3"且条件2中zeo_count=1,则发送字符串"拿取数量正确",否则发送拿取数量异常;若串口接收字符串为"4"且条件2中zeo_count=2,则发送字符串"拿取数量正确",否则发送拿取数量异常;若串口接收字符串为"5"且条件2中zeo_count=3,则发送字符串"拿取数量正确",否则发送拿取数量异常;若串口接收字符串为"6"且条件2中zeo_count=4,则发送字符串"拿取数量正确",否则发送拿取数量异常;若串口接收字符串为"7"且条件2中zeo_count=5,则发送字符串"拿取数量正确",否则发送拿取数量异常;若串口接收字符串为"8"且条件2中zeo_count=6,则发送字符串"拿取数量正确",否则发送拿取数量异常;若串口接收为空,则进入条件4;条件6.配置PA11引脚为下拉输入,读取PA11电平为高,进入条件5;若PA11电平为低,进入条件4

我可以回答这个问题。以下是代码：

#include "stm32f10x.h"
#include <stdio.h>
#include <string.h>

#define USART1_DR_Base 0x40013804

void USART1_Init(void);
void GPIO_Configuration(void);
void NVIC_Configuration(void);
void USART1_SendString(char* s);
void USART1_IRQHandler(void);

int main(void)
{
    GPIO_Configuration();
    USART1_Init();
    NVIC_Configuration();

    uint8_t last_zero_count = 0;
    uint8_t zero_count = 0;
    uint8_t buzzer_on = 0;

    while (1)
    {
        // Read the input pins
        uint8_t pin1 = GPIO_ReadInputDataBit(GPIOA, GPIO_Pin_1);
        uint8_t pin2 = GPIO_ReadInputDataBit(GPIOA, GPIO_Pin_2);
        uint8_t pin3 = GPIO_ReadInputDataBit(GPIOA, GPIO_Pin_3);
        uint8_t pin4 = GPIO_ReadInputDataBit(GPIOA, GPIO_Pin_4);
        uint8_t pin5 = GPIO_ReadInputDataBit(GPIOA, GPIO_Pin_5);
        uint8_t pin6 = GPIO_ReadInputDataBit(GPIOA, GPIO_Pin_6);

        // Convert the input pins to a binary string
        char binary[7];
        sprintf(binary, "%d%d%d%d%d%d", pin1, pin2, pin3, pin4, pin5, pin6);

        // Count the number of zeros in the binary string
        zero_count = 0;
        for (int i = 0; i < strlen(binary); i++)
        {
            if (binary[i] == '0')
            {
                zero_count++;
            }
        }

        // Send the binary string over USART1
        USART1_SendString(binary);

        // Compare the zero count to the last zero count
        if (zero_count < last_zero_count)
        {
            buzzer_on = 1;
        }
        last_zero_count = zero_count;

        // Wait for USART1 to receive a string
        while (USART_GetFlagStatus(USART1, USART_FLAG_RXNE) == RESET);

        // Read the received string
        char received[2];
        received[0] = USART_ReceiveData(USART1);
        received[1] = '\0';

        // Handle the received string
        if (strcmp(received, "1") == 0)
        {
            buzzer_on = 0;
        }
        else if (strcmp(received, "2") == 0)
        {
            buzzer_on = 1;
        }
        else if (strcmp(received, "3") == 0 && zero_count == 1)
        {
            USART1_SendString("拿取数量正确");
        }
        else if (strcmp(received, "4") == 0 && zero_count == 2)
        {
            USART1_SendString("拿取数量正确");
        }
        else if (strcmp(received, "5") == 0 && zero_count == 3)
        {
            USART1_SendString("拿取数量正确");
        }
        else if (strcmp(received, "6") == 0 && zero_count == 4)
        {
            USART1_SendString("拿取数量正确");
        }
        else if (strcmp(received, "7") == 0 && zero_count == 5)
        {
            USART1_SendString("拿取数量正确");
        }
        else if (strcmp(received, "8") == 0 && zero_count == 6)
        {
            USART1_SendString("拿取数量正确");
        }
        else if (received[0] == '\r' || received[0] == '\n')
        {
            // Do nothing
        }
        else
        {
            USART1_SendString("拿取数量异常");
        }

        // Turn the buzzer on or off
        if (buzzer_on)
        {
            GPIO_SetBits(GPIOB, GPIO_Pin_0);
        }
        else
        {
            GPIO_ResetBits(GPIOB, GPIO_Pin_0);
        }
    }
}

void GPIO_Configuration(void)
{
    GPIO_InitTypeDef GPIO_InitStructure;

    // Enable GPIOA and GPIOB clock
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA | RCC_APB2Periph_GPIOB, ENABLE);

    // Configure PA1, PA2, PA3, PA4, PA5, PA6 as input with pull-up
    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_1 | GPIO_Pin_2 | GPIO_Pin_3 | GPIO_Pin_4 | GPIO_Pin_5 | GPIO_Pin_6;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU;
    GPIO_Init(GPIOA, &GPIO_InitStructure);

    // Configure PA11 as input with pull-down
    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_11;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPD;
    GPIO_Init(GPIOA, &GPIO_InitStructure);

    // Configure PB0 as output
    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(GPIOB, &GPIO_InitStructure);
}

void USART1_Init(void)
{
    USART_InitTypeDef USART_InitStructure;

    // Enable USART1 clock
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1, ENABLE);

    // Configure USART1 TX and RX pins
    GPIO_InitTypeDef GPIO_InitStructure;
    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9 | GPIO_Pin_10;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(GPIOA, &GPIO_InitStructure);

    // Configure USART1
    USART_InitStructure.USART_BaudRate = 9600;
    USART_InitStructure.USART_WordLength = USART_WordLength_8b;
    USART_InitStructure.USART_StopBits = USART_StopBits_1;
    USART_InitStructure.USART_Parity = USART_Parity_No;
    USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;
    USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;
    USART_Init(USART1, &USART_InitStructure);

    // Enable USART1
    USART_Cmd(USART1, ENABLE);
}

void NVIC_Configuration(void)
{
    NVIC_InitTypeDef NVIC_InitStructure;

    // Configure the USART1 interrupt
    NVIC_InitStructure.NVIC_IRQChannel = USART1_IRQn;
    NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
    NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
    NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
    NVIC_Init(&NVIC_InitStructure);

    // Enable the USART1 receive interrupt
    USART_ITConfig(USART1, USART_IT_RXNE, ENABLE);
}

void USART1_SendString(char* s)
{
    while (*s)
    {
        while (USART_GetFlagStatus(USART1, USART_FLAG_TXE) == RESET);
        USART_SendData(USART1, *s++);
    }
}

void USART1_IRQHandler(void)
{
    if (USART_GetITStatus(USART1, USART_IT_RXNE) != RESET)
    {
        USART_ClearITPendingBit(USART1, USART_IT_RXNE);
    }
}

使用c++，给定字符串a，将它复制到字符串b并输出，必须用指针完成。

可以使用指针来完成字符串复制的操作，具体步骤如下：

1. 定义两个字符指针，分别指向字符串a和字符串b。
2. 使用循环遍历字符串a，将每个字符依次赋值给字符串b。
3. 注意在复制完最后一个字符后，要在字符串b的末尾添加一个空字符 '\0'，表示字符串的结束。

下面是完整的代码实现：

#include <iostream>
using namespace std;

int main() {
    char a[] = "hello world";
    char b[100];
    char *pa = a;  // 指向字符串a的指针
    char *pb = b;  // 指向字符串b的指针

    // 复制字符串
    while (*pa != '\0') {
        *pb = *pa;
        pa++;
        pb++;
    }
    *pb = '\0';  // 在字符串b末尾添加一个空字符

    // 输出字符串b
    cout << b << endl;

    return 0;
}

输出结果为：

hello world