Date Picker: Finished

[SpriggsySpriggs]

EDIT: So ok, I lied, I went through the painstaking process of finding C++ and Javascript functions for date calculation and converted them to QB64 code. Here is the ACTUAL finished product.
Here are the two links for the borrowed Javascript and C++ code: https://www.codespeedy.com/find-difference-between-two-dates-in-cpp/ and https://stackoverflow.com/a/13627586/4771393 and of course an edited version of the WeekDay$ function found in the help menu for DATE$.
Here is a finished version of the date picker I recently announced. It allows you to bring up a Windows Forms date picker and the script returns back the date using $LASTEXITCODE from PowerShell rather than outputting to a text file then reading it. Here is the code for the function that you can $INCLUDE at the end of your program as a BM to call a date picker object up whenever you feel like it. It returns the date formatted as MM-dd-yyyy. Maybe if someone wants to go through all the hullabaloo of using mathematics to compare the current date with the date that you pick then that would be a huge upgrade. I, however, don't feel like getting involved with a bunch of math.

Code: QB64: [Select]

1. 'OPTION _EXPLICIT
2. DIM date1 AS STRING
3. DIM date2 AS STRING
4.  
5. date1 = GetDate
6. date2 = GetDate
7. PRINT "The difference between "; date1$; " and "; date2$; " is "; RTRIM$(LTRIM$(STR$(difference_of_days(date1, date2)))); " days"
8. PRINT WeekDay(date1)
9. PRINT WeekDay(date2)
10.  
11. FUNCTION GetDate$
12.     DIM SHELL$
13.     DIM a AS LONG
14.     DIM datepicked AS STRING
15.     DIM month AS STRING
16.     DIM day AS STRING
17.     DIM year AS STRING
18.     SHELL$ = "PowerShell -WindowStyle Hidden -ExecutionPolicy Bypass " + CHR$(34) + "&'" + _STARTDIR$ + "\GetNewDate.ps1';exit $LASTEXITCODE" + CHR$(34)
19.     a = _SHELLHIDE(SHELL$)
20.     SELECT CASE LEN(LTRIM$(STR$(a)))
21.         CASE 7
22.             datepicked = LTRIM$(STR$(a))
23.             month = "0" + MID$(datepicked, 1, 1)
24.             day = MID$(datepicked, 2, 2)
25.             year = MID$(datepicked, 4, 4)
26.         CASE 8
27.             datepicked = LTRIM$(STR$(a))
28.             month = MID$(datepicked, 1, 2)
29.             day = MID$(datepicked, 3, 2)
30.             year = MID$(datepicked, 5, 4)
31.     END SELECT
32.     IF datepicked <> "" THEN
33.         GetDate = month + "-" + day + "-" + year
34.     ELSE
35.         GetDate = ""
36.     END IF
37. END FUNCTION
38.  
39. FUNCTION WeekDay$ (formatteddate AS STRING)
40.     DIM M
41.     DIM D
42.     DIM Y
43.     DIM C
44.     DIM S1
45.     DIM S2
46.     DIM S3
47.     DIM WkDay
48.     DIM day AS STRING
49.     DIM Moon AS STRING
50.     M = VAL(MID$(formatteddate, 1, 2))
51.     D = VAL(MID$(formatteddate, 4, 2))
52.     Y = VAL(MID$(formatteddate, 7, 4))
53.  
54.     IF M < 3 THEN M = M + 12: Y = Y - 1 'add 12 to Jan - Feb month, -1 year
55.     C = Y \ 100: Y = Y MOD 100 'split century and year number
56.     S1 = (C \ 4) - (2 * C) - 1 'century leap
57.     S2 = (5 * Y) \ 4 '4 year leap
58.     S3 = 26 * (M + 1) \ 10 'days in months
59.     WkDay = (S1 + S2 + S3 + D) MOD 7 'weekday total remainder
60.     IF WkDay < 0 THEN WkDay = WkDay + 7 'Adjust negative results to 0 to 6
61.     SELECT CASE WkDay
62.         CASE 0: day = "Sunday"
63.         CASE 1: day = "Monday"
64.         CASE 2: day = "Tuesday"
65.         CASE 3: day = "Wednesday"
66.         CASE 4: day = "Thursday"
67.         CASE 5: day = "Friday"
68.         CASE 6: day = "Saturday"
69.     END SELECT
70.     SELECT CASE M
71.         CASE 1: Moon = "January"
72.         CASE 2: Moon = "February"
73.         CASE 3: Moon = "March"
74.         CASE 4: Moon = "April"
75.         CASE 5: Moon = "May"
76.         CASE 6: Moon = "June"
77.         CASE 7: Moon = "July"
78.         CASE 8: Moon = "August"
79.         CASE 9: Moon = "September"
80.         CASE 10: Moon = "October"
81.         CASE 11: Moon = "November"
82.         CASE 12: Moon = "December"
83.     END SELECT
84.     WeekDay$ = day + ", " + Moon + " " + ordinal_suffix_of(LTRIM$(RTRIM$(STR$(D)))) + ", " + MID$(formatteddate, 7, 4)
85. END FUNCTION
86.  
87. FUNCTION ordinal_suffix_of$ (i AS STRING)
88.     DIM j
89.     DIM k
90.     j = VAL(i) MOD 10
91.     k = VAL(i) MOD 100
92.     IF j = 1 AND k <> 11 THEN
93.         ordinal_suffix_of = i + "st"
94.     ELSEIF j = 2 AND k <> 12 THEN
95.         ordinal_suffix_of = i + "nd"
96.     ELSEIF j = 3 AND k <> 13 THEN
97.         ordinal_suffix_of = i + "rd"
98.     ELSE
99.         ordinal_suffix_of = i + "th"
100.     END IF
101. END FUNCTION
102.  
103. FUNCTION check_leap_year (year AS LONG)
104.     IF year MOD 4 = 0 AND year MOD 100 <> 0 OR year MOD 400 = 0 THEN
105.         check_leap_year = 1
106.     ELSE
107.         check_leap_year = 0
108.     END IF
109. END FUNCTION
110.  
111. FUNCTION no_of_days_in_month (month AS LONG, year AS LONG)
112.     IF month = 1 OR month = 3 OR month = 5 OR month = 7 OR month = 8 OR month = 10 OR month = 12 THEN
113.         no_of_days_in_month = 31
114.     ELSEIF month = 4 OR month = 6 OR month = 9 OR month = 11 THEN
115.         no_of_days_in_month = 30
116.     ELSEIF month = 2 THEN
117.         DIM n AS LONG
118.         n = check_leap_year(year)
119.         IF n = 1 THEN
120.             no_of_days_in_month = 29
121.         ELSE
122.             no_of_days_in_month = 28
123.         END IF
124.     END IF
125. END FUNCTION
126.  
127. FUNCTION difference_of_days& (Date1 AS STRING, Date2 AS STRING)
128.     DIM month1
129.     DIM day1
130.     DIM year1
131.     DIM month2
132.     DIM day2
133.     DIM year2
134.  
135.     month1 = VAL(MID$(Date1, 1, 2))
136.     day1 = VAL(MID$(Date1, 4, 2))
137.     year1 = VAL(MID$(Date1, 7, 4))
138.  
139.     month2 = VAL(MID$(Date2, 1, 2))
140.     day2 = VAL(MID$(Date2, 4, 2))
141.     year2 = VAL(MID$(Date2, 7, 4))
142.  
143.     IF year1 = year2 THEN
144.         IF month1 = month2 THEN
145.             IF day1 = day2 THEN
146.                 difference_of_days = 0
147.                 EXIT FUNCTION
148.             ELSE
149.                 difference_of_days = ABS(day1 - day2)
150.                 EXIT FUNCTION
151.             END IF
152.         ELSEIF month1 < month2 THEN
153.             DIM result AS LONG
154.             DIM i
155.             FOR i = month1 TO month2 - 1
156.                 result = result + no_of_days_in_month(i, year1)
157.             NEXT
158.             IF day1 = day2 THEN
159.                 difference_of_days = result
160.                 EXIT FUNCTION
161.             ELSEIF day1 < day2 THEN
162.                 result = result + (day2 - day1)
163.                 difference_of_days = result
164.                 EXIT FUNCTION
165.             ELSE
166.                 result = result - (day1 - day2)
167.                 difference_of_days = result
168.                 EXIT FUNCTION
169.             END IF
170.         ELSE
171.             result = 0
172.             FOR i = month2 TO month1 - 1
173.                 result = result + no_of_days_in_month(i, year1)
174.             NEXT
175.             IF day1 = day2 THEN
176.                 difference_of_days = result
177.                 EXIT FUNCTION
178.             ELSEIF day2 < day1 THEN
179.                 result = result + (day1 - day2)
180.                 difference_of_days = result
181.                 EXIT FUNCTION
182.             ELSE
183.                 result = result - (day2 = day1)
184.                 difference_of_days = result
185.                 EXIT FUNCTION
186.             END IF
187.         END IF
188.     ELSEIF year1 < year2 THEN
189.         DIM temp AS LONG
190.         FOR i = year1 TO year2 - 1
191.             IF check_leap_year(i) = 1 THEN
192.                 temp = temp + 366
193.             ELSE
194.                 temp = temp + 365
195.             END IF
196.         NEXT
197.         IF month1 = month2 THEN
198.             IF day1 = day2 THEN
199.                 difference_of_days = temp
200.                 EXIT FUNCTION
201.             ELSEIF day1 < day2 THEN
202.                 difference_of_days = temp + (day2 - day1)
203.                 EXIT FUNCTION
204.             ELSE
205.                 difference_of_days = temp - (day1 - day2)
206.                 EXIT FUNCTION
207.             END IF
208.         ELSEIF month1 < month2 THEN
209.             result = 0
210.             FOR i = month1 TO month2 - 1
211.                 result = result + no_of_days_in_month(i, year2)
212.             NEXT
213.             IF day1 = day2 THEN
214.                 difference_of_days = temp + result
215.                 EXIT FUNCTION
216.             ELSEIF day1 < day2 THEN
217.                 result = result + (day2 - day1)
218.                 difference_of_days = temp + result
219.                 EXIT FUNCTION
220.             ELSE
221.                 result = result - (day1 - day2)
222.                 difference_of_days = temp + result
223.                 EXIT FUNCTION
224.             END IF
225.         ELSE
226.             result = 0
227.             FOR i = month2 TO month1 - 1
228.                 result = result + no_of_days_in_month(i, year2)
229.             NEXT
230.             IF day1 = day2 THEN
231.                 difference_of_days = temp - result
232.                 EXIT FUNCTION
233.             ELSEIF day2 < day2 THEN
234.                 result = result + (day1 - day2)
235.                 difference_of_days = temp - result
236.                 EXIT FUNCTION
237.             ELSE
238.                 result = result - (day2 - day1)
239.                 difference_of_days = temp - result
240.                 EXIT FUNCTION
241.             END IF
242.         END IF
243.     ELSE
244.         temp = 0
245.         FOR i = year2 TO year1 - 1
246.             IF check_leap_year(i) = 1 THEN
247.                 temp = temp + 366
248.             ELSE
249.                 temp = temp + 365
250.             END IF
251.         NEXT
252.         IF month1 = month2 THEN
253.             IF day1 = day2 THEN
254.                 difference_of_days = temp
255.                 EXIT FUNCTION
256.             ELSEIF day2 < day1 THEN
257.                 difference_of_days = temp + (day1 - day2)
258.                 EXIT FUNCTION
259.             ELSE
260.                 difference_of_days = temp - (day2 - day1)
261.                 EXIT FUNCTION
262.             END IF
263.         ELSEIF month2 < month1 THEN
264.             result = 0
265.             FOR i = month2 TO month1 - 1
266.                 result = result + no_of_days_in_month(i, year1)
267.             NEXT
268.             IF day1 = day2 THEN
269.                 difference_of_days = temp + result
270.                 EXIT FUNCTION
271.             ELSEIF day2 < day1 THEN
272.                 result = result + (day1 - day2)
273.                 difference_of_days = temp + result
274.                 EXIT FUNCTION
275.             ELSE
276.                 result = result - (day2 - day1)
277.                 difference_of_days = temp + result
278.                 EXIT FUNCTION
279.             END IF
280.         ELSE
281.             result = 0
282.             FOR i = month1 TO month2 - 1
283.                 result = result + no_of_days_in_month(i, year1)
284.             NEXT
285.             IF day1 = day2 THEN
286.                 difference_of_days = temp - result
287.                 EXIT FUNCTION
288.             ELSEIF day1 < day2 THEN
289.                 result = result + (day2 - day1)
290.                 difference_of_days = temp - result
291.                 EXIT FUNCTION
292.             ELSE
293.                 result = result - (day1 - day2)
294.                 difference_of_days = temp - result
295.                 EXIT FUNCTION
296.             END IF
297.         END IF
298.     END IF
299. END FUNCTION

GetNewDate.ps1