基于stm32设计一个计算器，通过键盘输入 0~9 的数字，以及运算法则加减乘除，能通过串口在电脑端串口调试软件上显示运算结果。写出完成此功能的所有代码

以下是基于STM32设计的计算器代码，可以通过串口在电脑端串口调试软件上显示运算结果：

#include "stm32f10x.h"
#include "stdio.h"

USART_InitTypeDef USART_InitStructure;

void GPIO_config(void)
{
    GPIO_InitTypeDef GPIO_InitStructure;
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);

    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(GPIOA, &GPIO_InitStructure);

    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
    GPIO_Init(GPIOA, &GPIO_InitStructure);
}

void USART_config(void)
{
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1, ENABLE);

    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);

    USART_Cmd(USART1, ENABLE);
}

void USART_send_char(char c)
{
    while (USART_GetFlagStatus(USART1, USART_FLAG_TXE) == RESET);
    USART_SendData(USART1, c);
}

void USART_send_string(char* s)
{
    while (*s)
    {
        USART_send_char(*s++);
    }
}

char USART_receive_char(void)
{
    while (USART_GetFlagStatus(USART1, USART_FLAG_RXNE) == RESET);
    return USART_ReceiveData(USART1);
}

int main(void)
{
    GPIO_config();
    USART_config();

    char buffer[50];
    char ch;
    int i = 0;

    while (1)
    {
        ch = USART_receive_char();
        if (ch != '\r')
        {
            buffer[i++] = ch;
        }
        else
        {
            buffer[i] = '\0';
            i = 0;
            int result = 0;
            int num1 = 0;
            int num2 = 0;
            char op;
            int flag = 0;
            for (int j = 0; buffer[j] != '\0'; j++)
            {
                if (buffer[j] >= '0' && buffer[j] <= '9')
                {
                    if (flag == 0)
                    {
                        num1 = num1 * 10 + (buffer[j] - '0');
                    }
                    else
                    {
                        num2 = num2 * 10 + (buffer[j] - '0');
                    }
                }
                else if (buffer[j] == '+' || buffer[j] == '-' || buffer[j] == '*' || buffer[j] == '/')
                {
                    op = buffer[j];
                    flag = 1;
                }
            }
            switch (op)
            {
            case '+':
                result = num1 + num2;
                break;
            case '-':
                result = num1 - num2;
                break;
            case '*':
                result = num1 * num2;
                break;
            case '/':
                result = num1 / num2;
                break;
            default:
                break;
            }
            sprintf(buffer, "%d\n", result);
            USART_send_string(buffer);
        }
    }
}

请注意，此代码仅为示例，仅支持简单的加减乘除运算，未做错误处理和输入检查。在实际应用中，需要根据具体要求进行修改和完善。