/* Generate random heights and weights, that are either  */
/* correlated or not, depending on what you want.        */
/*                                                       */
/* Written by Carey Williamson, University of Calgary    */
/*                                                       */
/* Usage: cc -o heights heights.c                        */
/*        ./heights                                      */

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

#define NUMPEOPLE 100   /* Number of people to simulate */

/* Debugging output */
#define DEBUG 1

/***********************************************************************/
/*                 RANDOM NUMBER GENERATION STUFF                      */
/***********************************************************************/

/* Parameters for random number generation. */
#define MAX_INT 2147483647       /* Maximum positive integer 2^31 - 1 */

/* Generate a random floating point value uniformly distributed in [0,1] */
float Uniform01()
  {
    float randnum;

    /* get a random positive integer from random() */
    randnum = (float) 1.0 * random();

    /* divide by max int to get something in (0..1)  */
    randnum = (float) randnum / (1.0 * MAX_INT); 

    return( randnum );
  }


/***********************************************************************/
/*                 MAIN PROGRAM                                        */
/***********************************************************************/

int main()
  {
    int i;
    float val, val2;
    float heights[NUMPEOPLE], weights[NUMPEOPLE];

    /* Initialization */
    srandom(1234567);

    for( i = 0; i < NUMPEOPLE; i++ )
      {
	val = Uniform01();
	heights[i] = val * (200 - 120) + 120;  /* Uniform(120,200) cm */
	val2 = Uniform01();
	if (val2 < 0.5 )
	  val = Uniform01();
	weights[i] = val * (100 - 30) + 30;    /* Uniform(30,100) kg */
#ifdef DEBUG
	printf("%4.1f %4.1f\n", heights[i], weights[i]);
#endif
      }
  }