mmxavg.c

Source code for an Numeric Cmputer

/********************************************************************
* Description: mmxavg.c
*   Min-max-average code
*
*   Derived from a work by Fred Proctor & Will Shackleford
*
* Author:
* License: GPL Version 2
* System: Linux
*    
* Copyright (c) 2004 All rights reserved.
*
* Last change:
* $Revision: 1.5 $
* $Author: yabosukz $
* $Date: 2005/07/08 14:11:06 $
********************************************************************/

#include "mmxavg.h"		/* these declarations */

#ifndef MAIN
/* MAIN not defined-- compile functions only, no main() */

int mmxavgInit(MMXAVG_STRUCT * mmxavg, double *space, int size)
{
    if (0 == mmxavg) {
	return -1;
    }
    mmxavg->nums = space;
    mmxavg->size = size;

    return mmxavgReset(mmxavg);
}

int mmxavgReset(MMXAVG_STRUCT * mmxavg)
{
    if (0 == mmxavg) {
	return -1;
    }
    mmxavg->sum = 0;
    mmxavg->index = 0;
    mmxavg->in = 0;
    mmxavg->inited = 0;
    mmxavg->min = 0.0;
    mmxavg->max = 0.0;

    return 0;
}

int mmxavgAdd(MMXAVG_STRUCT * mmxavg, double num)
{
    if (0 == mmxavg) {
	return -1;
    }
    if (mmxavg->index >= mmxavg->size || mmxavg->index < 0) {
	return -1;
    }
    if (mmxavg->in == mmxavg->size) {
	/* already full-- knock off oldest */
	mmxavg->sum -= mmxavg->nums[mmxavg->index];
    } else {
	mmxavg->in++;
    }

    mmxavg->nums[mmxavg->index] = num;
    mmxavg->sum += num;
    mmxavg->index++;
    if (mmxavg->index == mmxavg->size) {
	mmxavg->index = 0;
    }

    if (!mmxavg->inited) {
	mmxavg->min = num;
	mmxavg->max = num;
	mmxavg->inited = 1;
    } else if (num < mmxavg->min) {
	mmxavg->min = num;
    } else if (num > mmxavg->max) {
	mmxavg->max = num;
    }

    return 0;
}

double mmxavgMin(MMXAVG_STRUCT * mmxavg)
{
    if (0 == mmxavg) {
	return -1;
    }
    return mmxavg->min;
}

double mmxavgMax(MMXAVG_STRUCT * mmxavg)
{
    if (0 == mmxavg) {
	return -1;
    }
    return mmxavg->max;
}

double mmxavgAvg(MMXAVG_STRUCT * mmxavg)
{
    if (0 == mmxavg) {
	return -1;
    }
    if (mmxavg->in > 0) {
	return mmxavg->sum / mmxavg->in;
    } else {
	return 0.0;
    }
}

#else
/* MAIN defined */

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

/*
  syntax: mmx <size> {"min" | "max"}
  size is number of entries over which to average
  optional "min", "max" literals tell which to print, default is avg
  */
int main(int argc, char *argv[])
{
    MMXAVG_STRUCT mmxavg;
    int size;
    double *space;
    double num;
    int count = 0;
    int which = 3;		/* 1=min, 2=max, 3=avg printed */

    /* check args */
    if (argc < 2) {
	fprintf(stderr, "syntax: %s <size> {\"min\" | \"max\"}\n",
		argv[0]);
	exit(1);
    }

    /* read first mandatory arg */
    if (1 != sscanf(argv[1], "%d", &size) || size < 1) {
	fprintf(stderr, "size arg must be > 0\n");
	exit(1);
    }

    /* read optional args */
    if (argc > 2) {
	if (!strcmp(argv[2], "min")) {
	    which = 1;
	} else if (!strcmp(argv[2], "max")) {
	    which = 2;
	} else {
	    fprintf(stderr, "printing arg must be \"min\" or \"max\"\n");
	    exit(1);
	}
    }

    /* get space */
    space = (double *) malloc(size * sizeof(double));
    mmxavgInit(&mmxavg, space, size);

    while (!feof(stdin)) {
	if (1 != scanf("%lf", &num)) {
	    break;
	}

	mmxavgAdd(&mmxavg, num);

	if (which == 1)
	    printf("%d\t%f\n", count++, mmxavgMin(&mmxavg));
	else if (which == 2)
	    printf("%d\t%f\n", count++, mmxavgMax(&mmxavg));
	else
	    printf("%d\t%f\n", count++, mmxavgAvg(&mmxavg));
    }

    /* release space */
    free(space);

    exit(0);
}

#endif				/* MAIN defined */