Function for the difference in minutes between two times

[Jaze]

I previously posted this but later found an error. It takes two strings containing the time and date. It assumes the first string is the earlier of the two times. The time strings are in the format with one or two digits for hours, month and day. Assumes the time is in 12 hour time. For example, one valid string is 1:25 PM 12/7/2021

Code: QB64: [Select]

1. FUNCTION GetDifference (earlierTime$, moreRecentTime$)
2.     colonPosition1 = INSTR(earlierTime$, ":") 'format is H:MM #M M/D/YYYY to HH:MM #M MM/DD/YYYY so finging the colon is needed
3.     colonPosition2 = INSTR(moreRecentTime$, ":") 'same
4.     hours1 = VAL(LEFT$(earlierTime$, colonPosition1 - 1)) 'hours portion of the time
5.     hours2 = VAL(LEFT$(moreRecentTime$, colonPosition2 - 1))
6.     minutes1 = VAL(MID$(earlierTime$, colonPosition1 + 1, 2)) ' minutes portion of the time
7.     minutes2 = VAL(MID$(moreRecentTime$, colonPosition2 + 1, 2))
8.     IF MID$(earlierTime$, colonPosition1 + 4, 1) = "P" AND hours1 <> 12 THEN hours1 = hours1 + 12 'convert to 24hr
9.     IF MID$(moreRecentTime$, colonPosition2 + 4, 1) = "P" AND hours2 <> 12 THEN hours2 = hours2 + 12
10.     month1 = VAL(LTRIM$(MID$(earlierTime$, INSTR(earlierTime$, "/") - 2, 2))) 'the month of the earlier string
11.     month2 = VAL(LTRIM$(MID$(moreRecentTime$, INSTR(moreRecentTime$, "/") - 2, 2))) 'month of the later string
12.     rightCut1$ = MID$(earlierTime$, INSTR(earlierTime$, "/") + 1, LEN(earlierTime$)) 'cut the string to find the 2nd "/"
13.     rightcut2$ = MID$(moreRecentTime$, INSTR(moreRecentTime$, "/") + 1, LEN(moreRecentTime$))
14.     day1 = VAL(LEFT$(rightCut1$, INSTR(rightCut1$, "/") - 1)) 'get the day of the month
15.     day2 = VAL(LEFT$(rightcut2$, INSTR(rightcut2$, "/") - 1))
16.     year1 = VAL(MID$(rightCut1$, INSTR(rightCut1$, "/") + 1, 4)) 'and finally the year
17.     year2 = VAL(MID$(rightcut2$, INSTR(rightcut2$, "/") + 1, 4))
18.     IF hours1 = 24 THEN hours1 = 0 'puts midnight to hour 0
19.     IF hours2 = 24 THEN hours2 = 0
20.     minutesDifferent = 0 'initialize the number of minutes the two times differ
21.     currentMinute = minutes1 'hours, minutes, days, months and years need to stay the same to exit the following loop
22.     currentHour = hours1
23.     currentDay = day1
24.     currentMonth = month1
25.     currentYear = year1
26.     DO
27.         minutesDifferent = minutesDifferent + 1 'increment the number of minutes different
28.         currentMinute = currentMinute + 1 'move the counter for exiting the loop
29.         IF currentMinute = 60 THEN '60 minutes is the next hour
30.             currentMinute = 0
31.             currentHour = currentHour + 1
32.             IF currentHour = 24 THEN 'go to the next day
33.                 currentHour = 0
34.                 currentDay = currentDay + 1
35.                 IF currentDay >= 28 THEN 'see if the months needs to be incremented and do so when it is needed
36.                     SELECT CASE currentMonth
37.                         CASE 4, 6, 9, 11 'April, June, September and November have 30 days
38.                             IF currentDay = 31 THEN 'increment the month
39.                                 currentMonth = currentMonth + 1
40.                                 currentDay = 1
41.                             END IF
42.                         CASE 1, 3, 5, 7, 8, 10, 12 'January, March, May, July, August, October and December
43.                             IF currentDay = 32 THEN 'increment the month
44.                                 currentMonth = currentMonth + 1
45.                                 currentDay = 1
46.                             END IF
47.                         CASE 2 'february
48.                             IF currentDay = 29 AND currentYear MOD 4 <> 0 THEN 'if not a leap year, increment the month
49.                                 currentMonth = 3
50.                                 currentDay = 1
51.                             ELSEIF currentDay = 30 AND currentYear MOD 4 = 0 THEN 'if is leap year, increment month
52.                                 currentMonth = 3
53.                                 currentDay = 1
54.                             END IF
55.                     END SELECT
56.                     IF currentMonth = 13 THEN 'increment the year
57.                         currentYear = currentYear + 1
58.                         currentMonth = 1
59.                     END IF
60.                 END IF
61.             END IF
62.         END IF
63.     LOOP UNTIL (currentHour = hours2 AND currentMinute = minutes2 AND currentMonth = month2 AND currentDay = day2 AND currentYear = year2)
64.     GetDifference = minutesDifferent
65. END FUNCTION
66.