C++实用小程序

1.linux C++ 获取当前系统时间（毫秒级）

#include <stdio.h>
#include <sys/time.h>

using namespace std;

void sysTime(string &currentTime)
{
    struct timeval tv;
    struct timezone tz;
    struct tm *t;
    char * curTime;

    gettimeofday(&tv, &tz);
    t = localtime(&tv.tv_sec);
    sprintf(curTime, "%d-%d-%d_%d%d%d%ld", 1900+t->tm_year, 1+t->tm_mon, t->tm_mday, t->tm_hour, t->tm_min, t->tm_sec, tv.tv_usec);
    currentTime = curTime;
}

int main()  
{  
    string  currentTime;
    sysTime(currentTime);
    cout<<"current time :"<<currentTime<<endl;
    return 0;  

2.滑动窗口滤波函数

/*********************** 滑动窗口滤波函数 ****************************/
float LatticePlannerNode::slidingAverageFilter(float value, const int window_size, float *buffer)
{
  static int data_num = 0;
  float output = 0;

  if (data_num < window_size) //不满窗口，先填充
  {
    buffer[data_num++] = value;
    output = value; //返回相同的值
  }
  else
  { 
    int i = 0;
    float sum = 0;

    memcpy(&buffer[0], &buffer[1], (window_size - 1) * 4); //将1之后的数据移到0之后，即移除头部
    buffer[window_size - 1] = value;                       //即添加尾部

    for (i = 0; i < window_size; i++) //每一次都计算，可以避免累计浮点计算误差
      sum += buffer[i];

    output = sum / window_size;
  }

  return output;
}