#include <stdio.h>
#include <string.h>
#include <sqlenv.h>
#include <sqlutil.h>

EXEC SQL INCLUDE SQLCA;

EXEC SQL BEGIN DECLARE SECTION;
  short sid;
	char  first[21];
	char  last[21];
	short points;
EXEC SQL END DECLARE SECTION;

#define N 100

struct {
	int   nonempty;    /* 0: no student in this group */
	short sid;
	char  first[21];
	char  last[21];
	int   sum_points;
} group[N];

int main(void)
{
	int g;
	
	EXEC SQL CONNECT TO homework;
	
	EXEC SQL WHENEVER SQLERROR GOTO error;
		
	EXEC SQL DECLARE c1 CURSOR FOR
	  SELECT   s.SID, s.FIRST, s.LAST, r.POINTS
		FROM     STUDENTS s, RESULTS r
		WHERE    s.SID = r.SID;
	
	EXEC SQL OPEN c1;
	EXEC SQL WHENEVER NOT FOUND GOTO done;
	
	while (1) {
		EXEC SQL FETCH c1 INTO :sid, :first, :last, :points;
		
		if (group[sid % N].nonempty) 
			group[sid % N].sum_points += points;
		else {
			group[sid % N].nonempty   = 1;
			group[sid % N].sum_points = points;
			group[sid % N].sid        = sid;
			strncpy(group[sid % N].first, first, 20);
			strncpy(group[sid % N].last, last, 20);
		}
	}
	
done:
	EXEC SQL CLOSE c1;
		
	for (g = 0; g < N; g++)	
		if (group[g].nonempty) 
			printf("#%d %10s %10s\t %d points\n", 
				group[g].sid,
				group[g].first,
				group[g].last,
				group[g].sum_points);

	EXEC SQL COMMIT;
	
	return 0;

error:
	EXEC SQL WHENEVER SQLERROR CONTINUE;
	
	printf ("DB2 error (%d, %s)\n", sqlca.sqlcode, sqlca.sqlstate);
	if (sqlca.sqlerrml)
		printf("\t%.*s\n", sqlca.sqlerrml, sqlca.sqlerrmc);
	
	EXEC SQL ROLLBACK;
	
	return 1;
}