使用标准库，编写stm32f103c8t6通过USART2串口输出数值的程序

好的，这里给你提供一个示例程序，使用USART2串口输出ADC1采集的值：

#include "stm32f10x.h"

void USART2_Init(void)
{
    GPIO_InitTypeDef GPIO_InitStructure;
    USART_InitTypeDef USART_InitStructure;

    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA | RCC_APB2Periph_AFIO, ENABLE);
    RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART2, ENABLE);

    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_2;
    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_3;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
    GPIO_Init(GPIOA, &GPIO_InitStructure);

    USART_InitStructure.USART_BaudRate = 115200;
    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_Tx;
    USART_Init(USART2, &USART_InitStructure);

    USART_Cmd(USART2, ENABLE);
}

void ADC1_Init(void)
{
    GPIO_InitTypeDef GPIO_InitStructure;
    ADC_InitTypeDef ADC_InitStructure;

    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA | RCC_APB2Periph_ADC1, ENABLE);

    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AIN;
    GPIO_Init(GPIOA, &GPIO_InitStructure);

    ADC_DeInit(ADC1);

    ADC_InitStructure.ADC_Mode = ADC_Mode_Independent;
    ADC_InitStructure.ADC_ScanConvMode = DISABLE;
    ADC_InitStructure.ADC_ContinuousConvMode = DISABLE;
    ADC_InitStructure.ADC_ExternalTrigConv = ADC_ExternalTrigConv_None;
    ADC_InitStructure.ADC_DataAlign = ADC_DataAlign_Right;
    ADC_InitStructure.ADC_NbrOfChannel = 1;
    ADC_Init(ADC1, &ADC_InitStructure);

    ADC_Cmd(ADC1, ENABLE);

    ADC_ResetCalibration(ADC1);

    while (ADC_GetResetCalibrationStatus(ADC1))
        ;

    ADC_StartCalibration(ADC1);

    while (ADC_GetCalibrationStatus(ADC1))
        ;
}

int main(void)
{
    USART2_Init();
    ADC1_Init();

    while (1)
    {
        ADC_SoftwareStartConvCmd(ADC1, ENABLE);

        while (!ADC_GetFlagStatus(ADC1, ADC_FLAG_EOC))
            ;

        uint16_t value = ADC_GetConversionValue(ADC1);
        char buf[16];
        sprintf(buf, "%d\r\n", value);
        int len = strlen(buf);
        for (int i = 0; i < len; i++)
            USART_SendData(USART2, buf[i]);

        for (int i = 0; i < 1000000; i++)
            ;
    }
}

这个程序使用USART2串口输出ADC1采集的值，波特率为115200。注意，本程序只是一个示例，实际应用中需要根据具体情况进行修改。