running-average.c

running-average.c

#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>

struct running_average {
  float average;
  uint32_t count;
} typedef running_average;

void initialize(running_average* ra) {
  ra->average = 0;
  ra->count = 0;
}

void update(running_average* ra, const uint32_t x) {
  if (ra->count == 0) {
    ra->average = x;
    ra->count = 1;
    return;
  }

  ra->count += 1;

  float a = (float)x / (float)ra->count;
  float b = ra->average + a;

  ra->average = b - (ra->average / (float)ra->count);
}

int main(int argc, char** argv) {
  running_average ra;

  initialize(&ra);

  //  for (int i = 0; i < 1000; i += 1) {
  //    uint32_t x = arc4random();

  printf("%zu\n", sizeof(float));
  //    update(&ra, x);
  update(&ra, 0xffffffff);
  printf("x = %u, %f\n", 0xffffffff, ra.average);
  update(&ra, 0xffffffff);
  printf("x = %u, %f\n", 0xffffffff, ra.average);
  update(&ra, 0xffffffff);
  printf("x = %u, %f\n", 0xffffffff, ra.average);
  update(&ra, 1);
  printf("x = %u, %f\n", 1, ra.average);
  update(&ra, 0x0fffffff);
  printf("x = %u, %f\n", 0x0fffffff, ra.average);
  update(&ra, 0xffffffff);
  printf("x = %u, %f\n", 0xffffffff, ra.average);



  
  //    printf("x = %u, new average = %f\n", x, ra.average);
    //  }
}