垃圾值不知道它来自哪里

Question

我的代码有问题，我一直在它几个小时，现在试图发现问题，但无法确定原因。当我在屏幕上打印时，所有的值都应该等于零，但是angleY变量应该为零时会一直打印出34244。我想看看有没有人能告诉我这个价值是从哪里来的？为什么？我有printf("current rate: %d angle rate: %d angle rate: %d previous rate: %d \n",currentRateY, angleRateY, angleY, previousRateY);这行打印所有变量的值，所以我可以精确定位问题，并且所有变量保持0，直到angleY变量。我的代码如下：

#include <stdio.h> 
#include <string.h> 
#include <errno.h> 
#include <unistd.h> 
#include <stdlib.h> 
#include <stdint.h> 
#include <time.h> 
#include <wiringPi.h> 
#include <wiringPiI2C.h> 

#define CTRL_REG1 0x20 
#define CTRL_REG2 0x21 
#define CTRL_REG3 0x22 
#define CTRL_REG4 0x23 


int fd; 
short x = 0; 
short y = 0; 
short z = 0; 
int main(){ 



    fd = wiringPiI2CSetup(0x69); // I2C address of gyro 
    wiringPiI2CWriteReg8(fd, CTRL_REG1, 0x1F); //Turn on all axes, disable power down 
    wiringPiI2CWriteReg8(fd, CTRL_REG3, 0x08); //Enable control ready signal 
    wiringPiI2CWriteReg8(fd, CTRL_REG4, 0x80); // Set scale (500 deg/sec) 
    delay(200);     // Wait to synchronize 

void getGyroValues(){ 
    int MSB, LSB; 

    LSB = wiringPiI2CReadReg8(fd, 0x28); 
    MSB = wiringPiI2CReadReg8(fd, 0x29); 
    x = ((MSB << 8) | LSB); 

    MSB = wiringPiI2CReadReg8(fd, 0x2B); 
    LSB = wiringPiI2CReadReg8(fd, 0x2A); 
    y = ((MSB << 8) | LSB); 

    MSB = wiringPiI2CReadReg8(fd, 0x2D); 
    LSB = wiringPiI2CReadReg8(fd, 0x2C); 
    z = ((MSB << 8) | LSB); 
} 
    for (int i=0;i<1000;i++){ 

     getGyroValues(); 

    int previousRateZ = z /114; 
    int previousRateY = y /114; 
    int previousRateX = x /114; 

     delay(100); 

     getGyroValues(); 

    int currentRateZ = z /114; 
    int currentRateY = y /114; 
    int currentRateX = x /114; 

    int angleRateZ = ((long)(previousRateZ + currentRateZ) * 105)/1000; 
    int angleRateY = ((long)(previousRateY + currentRateY) * 105)/1000; 
    int angleRateX = ((long)(previousRateX + currentRateX) * 105)/1000; 

    int angleZ = angleZ + angleRateZ; 
    int angleY = angleY + angleRateY; 
    int angleX = angleX + angleRateX; 
    printf("current rate: %d angle rate: %d angle rate: %d previous rate: %d \n",currentRateY, angleRateY, angleY, previousRateY); 
     delay(100); 

    if(i == 1){ 
     printf("Z equals: %d\n", angleZ); 
     printf("Y equals: %d\n", angleY); 
    printf("X equals: %d\n", angleX); 
    i=0; 
    } 
} 


}; 

Answer 1

你在这一行设置之前，使用angleY：

int angleY = angleY + angleRateY; 

C不保证值初始化为零。我想你真的想要这样的事情：

int angleY = 0; 
angleY = angleY + angleRateY; 

我也假设第二行将在未来版本的某种循环中结束。