This is some _Mem coding for prime numbers:
![[Image: memory2.png]](https://i.ibb.co/KMdh2Hj/memory2.png)
Code: (Select All)
Rem example using _mem functions with primes. v1.0a 01/30/2025 QB64 PD 2025.
Rem written by Erik Jon Oredson at eoredson@gmail.com
$Checking:Off
_ScreenMove _Middle
Dim m As _MEM
Dim n As _MEM
Dim p As _Offset
Color 15
Print "Mem sample program v1.0a"
Print "Prime value(10-32767)";
Input t
If t >= 10 And t <= 32767 Then
Else
End
End If
' length of mem prime value
l = GetPrime(t)
l$ = LTrim$(Str$(l))
l = Len(l$)
' define length of memory buffer
m = _MemNew(t * l + l)
n = _MemNew(t * l + l)
p = m.TYPE
' perform the memory functions
GoSub PutMem
GoSub CopyMem
GoSub GetMem
GoSub FreeMem
' take apart the memory buffer
Color 14
Print "Display memory buffer."
Print " Memtype:"; p ' ; "("; _Bin$(p); ")"
For q = 1 To t
z = Int(Val(Mid$(b$, (q - 1) * l + 1, l)))
Print z;
Next
Print
x = More
Color 7
End
' store the memory buffer
PutMem:
Color 14
For q = 1 To t
w = GetPrime(q)
x$ = String$(l, "0")
s$ = s$ + Right$(x$ + LTrim$(Str$(w)), l)
Next
Print "Store memory buffer."
x = Display(s$)
_MemPut m, m.OFFSET, s$
Return
' copy the memory buffer
CopyMem:
Color 14
s$ = Space$(t * l)
_MemGet m, m.OFFSET, s$
Print "Copy memory buffer."
x = Display(s$)
_MemCopy m, m.OFFSET, m.SIZE To n, n.OFFSET
Return
' read the memory buffer
GetMem:
Color 14
b$ = Space$(t * l)
_MemGet n, n.OFFSET, b$
Print "Read memory buffer."
x = Display(b$)
Return
' always clear the memory when done
FreeMem:
Color 14
Print "Free memory buffer."
_MemFree m: _MemFree n
x = More
Return
' prompt for next display
Function More
Color 15
Print "-more-";
Do
_Limit 50
x$ = InKey$
If Len(x$) Then
Print
Exit Do
End If
Loop
More = -1
End Function
' prompt for next display
Function MoreX
Color 15
Print "-next-";
Do
_Limit 50
x$ = InKey$
If Len(x$) Then
Print
Exit Do
End If
Loop
MoreX = -1
End Function
Function Display (o$)
c = -1
For d = 1 To Len(o$)
c = c + 1
If c >= 22 * 80 Then
c = 0
Print
x = MoreX
End If
Color 14
Print Mid$(o$, d, 1);
Next
Print
x = More
Display = -1
End Function
Function GetPrime (Temp#)
PrimeNumber# = Int(Temp#)
If PrimeNumber# <= 0# Then
Prime# = 0
End If
If PrimeNumber# = 1# Then
Prime# = 2
End If
If PrimeNumber# > 1# Then
PrimeCounter# = 0
PrimeNumber# = PrimeNumber# + 1#
Do
Prime# = Prime# + 1
PrimeFlag = 0
For Factor# = 2 To Int(Sqr(Prime#))
If Prime# / Factor# = Int(Prime# / Factor#) Then
PrimeFlag = -1
Exit For
End If
Next
If PrimeFlag = 0 Then
PrimeCounter# = PrimeCounter# + 1
End If
If PrimeCounter# = PrimeNumber# Then
Exit Do
End If
Loop
End If
Temp# = Prime#
GetPrime = Temp#
End Function