simplify erro checking

Author: fsaadatmand

chapter05/5-9.c

@@ -1,6 +1,7 @@
 /*
  * Exercise 5-9. Rewrite the routine day_of_year and month_day with pointers
  * instead of indexing.
+ *
  * By Faisal Saadatmand
  */
 
@@ -9,9 +10,9 @@
 /* functions */
 int day_of_year(int, int, int);
 void month_day(int, int, int *, int *);
-char *month_name(int ); 
+char *month_name(int); 
 
-static char daytab[2][13] = {
+static char daytab[][13] = {
 	{0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31},
 	{0, 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}
 };
@@ -24,18 +25,11 @@ int day_of_year(int year, int month, int day)
 {
 	int i, leap;
 
-	if ((year < 1) || (month < 1 && month > 12) || (day < 1 && day > 31))
+	if ((year < 1) || month < 1 || month > 12 || day < 1 || day > 31)
 		return -1;
-
 	leap = (year % 4 == 0 && year % 100) || year % 400 == 0;
-	
 	for (i = 1; i < month; i++)
-		day += *((*(pdaytab + leap)) + i); 
-		//day += *(daytab[leap] + i);
-		//day += (*(daytab + leap)) [i];
-		//day += *((*(daytab + leap)) + i);
-		//day += *(&daytab[0][0] + 4 * leap + i);
-
+		day += *(*(pdaytab + leap) + i); 
 	return day;
 }
 
@@ -44,14 +38,15 @@ void month_day(int year, int yearday, int *pmonth, int *pday)
 {
 	int i, leap;
 
+	if (year < 0 || yearday < 1 || yearday > 366) {
+		*pmonth = *pday =  0;
+		return;
+	}
 	leap = (year % 4 == 0 && year % 100) || year % 400 == 0;
-
 	for (i = 1; yearday > daytab[leap][i]; i++)
 		yearday -= *(*(pdaytab + leap) + i); 
-
-	(i < 1 || i > 12 || year < 1) ? (*pmonth = **pdaytab) : (*pmonth = i);
-	(yearday < 1 || yearday > 366 || year < 1) ? (*pday = **pdaytab) : 
-		(*pday = yearday);
+	*pmonth = i;
+	*pday = yearday;
 }
 
 /* month_name: return name of n-th month */
@@ -72,17 +67,14 @@ int main(void)
 {
 	int yearday, month, day;
 
-	if ((yearday = day_of_year(2018, 9, 3)) >= 0)
-		printf("%i day of the year\n", yearday);
+	if ((yearday = day_of_year(2018, 9, 3)) < 0)
+		printf("Invalid input\n");
 	else
-		printf("invalid input\n");
-
+		printf("day of the year: %i\n", yearday);
 	month_day(2018, 246, &month, &day);
-
-	if (month != 0 && day != 0)
-		printf("%s %i\n", month_name(month), day);
+	if (!month || !day)
+		printf("Invalid input\n");
 	else
-		printf("invalid input\n");
-
+		printf("%s %i\n", month_name(month), day);
 	return 0;
 }