Xor Magic ^2

[bplus]

@NOVARSEG not seeing the relationship to Xor in your last posts.

[SpriggsySpriggs]

Could be another hijacked post!

[NOVARSEG]

Yep the thread went off topic but did not want to start a new thread

 XOR and other logic operators combined with memput and memget allow full control of cursor position and color


The code was just a simplified version.  I think XOR can be used to turn a cursor on and off.

[bplus]

More Xor Magic, use Xor to find the missing number from a set of integers from 1 to n:

Code: QB64: [Select]

1. _Title "Find missing number" 'b+ 2021-04-12
2. ' given an array of integers for 1 to n find the missing integer
3.  
4. Randomize Timer
5. DefLng A-Z
6. n = Int(Rnd * 100) + 2 ' pick a number n of integers
7. Dim nums(1 To n) ' set an array of numbers
8. For i = 1 To n: nums(i) = i: Next
9. For i = n To 2 Step -1 ' shuffle  the array
10.     Swap nums(Int(i * Rnd) + 1), nums(i)
11. Next
12.  
13. 'remove one of the integers
14. r = Int(n * Rnd) + 1
15. removed = nums(r) 'save number
16. nums(r) = 0
17.  
18. 'find missing number  one way to find the missing number
19. For i = 1 To n
20.     sum = sum + nums(i)
21. Next
22. missing = n * (n + 1) / 2 - sum 'subtract sum from the formula for sum of integers 1 to n = n*(n+1)/2
23. Print "Missing number found by difference for formula for sum of 1 to n integers and sum of integers in array."
24. Print missing, removed
25.  
26. ' now we shall find the missing number using Xor alone!
27. missing = 0
28. For i = 1 To n
29.     missing = missing Xor i
30.     missing = missing Xor nums(i)
31. Next
32. Print: Print "Xor found missing compared to removed was:"
33. Print missing, removed
34.  
35.  

[NOVARSEG]

Can Alice and Bob find the missing number?

[bplus]

And Bob and Alice can create a deck of 52 shuffled numbers using Xor (instead of =):

Code: QB64: [Select]

1. _Title "Find duplicate number" 'b+ 2021-04-13
2. ' lets create a deck of 52 shuffled numbers with Xor
3.  
4. Randomize Timer
5. DefLng A-Z 'every variable, array and function is long
6.  
7. ReDim nums(1 To 52) ' set an array of numbers
8.  
9. 'obviously the first pick won't duplicate
10. nums(1) = RandomPicker1To52
11. index = 2
12.  
13. pickAgain:
14. pick = RandomPicker1To52
15. For i = 1 To index - 1
16.     If (nums(i) Xor pick) = 0 Then GoTo pickAgain 'it was a duplicate
17. Next
18. nums(index) = pick
19. index = index + 1
20. If index <= 52 GoTo pickAgain
21.  
22. 'display results
23. For i = 1 To 52: Print nums(i);: Next  'shouldn't be any duplicates or missing numbers, 1 to 52
24.  
25. Function RandomPicker1To52
26.     RandomPicker1To52 = Int(Rnd * 52) + 1
27. End Function
28.  
29.