/*
 * PLANETS1 -- sort and print planets in increasing order of diameter
 * this uses parallel arrays to hold names and diameters
 *
 * Usage: planets1
 *     
 * Inputs: none
 * Outputs: prints the sorted list
 *      
 * Written by Matt Bishop for ECS 30
 * version 1    November 18, 2015
 */             

#include <stdio.h>

/*
 * arrays of planet names and diameters
 * NOTE -- the index for each diameter *must*
 * match the index for that planet, so if the
 * IAU promotes Ceres, be sure you put both the
 * name *and* diameter in the fifth position
 * (fourth for zero-based counting), after Mars
 * but before Jupiter, of their respective
 * arrays
 */
char *names[] = {	/* planet names */
	"Mercury",
	"Venus",
	"Earth",
	"Mars",
	"Jupiter",
	"Saturn",
	"Uranus",
	"Neptune",
	"Pluto",
};
/* number of entries */
int sz_names = sizeof(names) / sizeof(char *);

int diameters[] = {	/* planet diameters */
	4780,			/* Mercury */
	12104,			/* Venus */
	12756,			/* Earth */
	6780,			/* Mars */
	139822,			/* Jupiter */
	116464,			/* Saturn */
	50724,			/* Uranus */
	49248,			/* Neptune */
	2400,			/* Pluto */
};
/* number of entries */
int sz_diameters = sizeof(diameters) / sizeof(int);

/*
 * main routine
 */
int main(void)
{
	char *tmp_names;	/* temporary to hold name pointer in swap */
	int tmp_diameters;	/* temporary to hold diameter in swap */
	int i, j;		/* counters in for loops */
	int min;		/* index of minimum diameter this pass */

	/*
	 * do selection sort
	 * make repeated passes through the list,
	 * putting the planet with the minimum diameter in the
	 * first position, and then sorting the rest of the list
	 */
	for(i = 0; i < sz_diameters; i++){
		/* assume first one is minimum diameter */
		min = i;
		/*
		 * now find out if it *really* is the minimum
		 * if not, swap it with the minimum and continue
		 */
		for(j = i + 1; j < sz_diameters; j++)
			if (diameters[j] < diameters[min])
				min = j;

		/*
		 * if we found a new minimum -- swap 
		 * note we have to swap names too
		 */
		if (min != i){
			/* diameter first */
			tmp_diameters = diameters[min];
			diameters[min] = diameters[i];
			diameters[i] = tmp_diameters;
			/* then name */
			tmp_names = names[min];
			names[min] = names[i];
			names[i] = tmp_names;
		}
	}

	/*
	 * now print out the planets and diameters
	 * in increasing order of diameter
	 */
	printf("Planets in order of size of diameters:\n");
	for(i = 0; i < sz_diameters; i++)
		printf("%7dkm  %s\n", diameters[i], names[i]);
	
	/*
	 * all done!
	 */
	return(0);
}