/* This program opens a file called "scores" that is formatted into
 * five columns: one with the social security number of the student,
 * and then the grades for program 1, program 2, test 1, and test 2.
 *
 * It figures out the weighted average for each student according to
 *
 *		prog1 = 10% of grade
 *		prog2 = 20% of grade
 *		test1 = 30% of grade
 *		test2 = 40% of grade
 *
 * It also prints the SSN of the student with the best average, and the 
 * average for the class.
 *
 * Programs are graded on a scale of 1..10, test from 1..100.  We want
 * the average to be calculated in terms of 1..100.
 */

#include <stdio.h>

int main () {
	int	ssn, 		/* current SSN */
		best_ssn, 	/* SSN of best student */
		n;		/* number of students */
	float	average, 	/* average for current student */
		class_average, 	/* average for class */
		best_average, 	/* average for best student */
		prog1, 		/* grades for prog1, prog2, ... */
		prog2, 
		test1, 
		test2;
	FILE	*f;		/* file pointer */

	/* open the "scores" file for reading */

	f = fopen ("scores", "r");

	/* initialize averages, etc. to 0 */

	class_average = 0.0;
	best_average = 0.0;
	best_ssn = 0;
	n = 0;

	/* read in the first student record */

	fscanf (f, "%d %f %f %f %f", &ssn, &prog1, &prog2, &test1, &test2);

	/* while not at the end of this file... */

	while (!feof (f)) {

		/* one more student */

		n++;

		/* figure out average, scaling programs up to 1..100 */

		average = 0.10 * (prog1 * 10)
			+ 0.20 * (prog2 * 10)
			+ 0.30 * test1
			+ 0.40 * test2;

		/* accumulate averages in class_average, later we
		 * will divide by n
	 	 */

		class_average += average;

		/* if this average is better than current best average... */
		if (average > best_average) {
			/* ... save it and the ssn */

			best_average = average;
			best_ssn = ssn;
		}

		/* print out the current student's information */

		printf ("SSN %d; grade %6.2f\n", ssn, average);

		/* get another student record */

		fscanf (f, "%d %f %f %f %f", &ssn, &prog1, &prog2, &test1, &test2);
	}

	/* close the file */

	fclose (f);

	/* print the average and SSN for the best student */

	printf ("best student has ssn %d with score %6.2f\n", 
		best_ssn, best_average);

	/* figure out class average (dividing the sum by number of students) */

	class_average /= n;

	/* print class average */

	printf ("class average is %6.2f\n", class_average);
}