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急：验证歌德巴赫猜想：一个大偶数可以分解为两个素数之和。试编程将500-1000之间的全部偶数表示为两个素数之和
验证歌德巴赫猜想：一个大偶数可以分解为两个素数之和。试编程将500-1000之间的全部偶数表示为两个素数之和
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skytears 2003-12-25
sorry,写错了，更正如下：
Function primeStatus(a As Integer) As Boolean
Dim i As Integer
Dim j As Integer
For i = 2 To a - 1
If a Mod i = 0 Then
primeStatus = False
Exit Function
End If
Next i
primeStatus = True
End Function
Private Sub Command1_Click()
Dim i As Integer
Dim j As Integer
For i = 500 To 1000 Step 2
For j = 1 To i - 1
If primeStatus(j) Then
If primeStatus(i - j) Then
Debug.Print i & " = " & j & " + " & (i - j)
End If
End If
Next j
Next i
End Sub
Function primeStatus(a As Integer) As Boolean
Dim i As Integer
Dim j As Integer
For i = 2 To a - 1
If a Mod i = 0 Then
primeStatus = False
Exit Function
End If
Next i
primeStatus = True
End Function
Private Sub Command1_Click()
Dim i As Integer
Dim j As Integer
For i = 500 To 1000 Step 2
For j = 1 To i - 1
If primeStatus(j) Then
If primeStatus(i - j) Then
Debug.Print i & " = " & j & " + " & (i - j)
End If
End If
Next j
Next i
End Sub
skytears 2003-12-25
已经解决,谢谢各位
Function primeStatus(a As Integer) As Boolean
Dim i As Integer
Dim j As Integer
For i = 2 To a - 1
If a Mod i = 0 Then
primeStatus = False
Exit Function
End If
Next i
primeStatus = True
End Function
Private Sub Command1_Click()
Dim i As Integer
'Dim j As Integer
For i = 500 To 1000
If i Mod 2 = 0 Then
If primeStatus(i \ 2) Then
Print i;
End If
End If
Next i
End Sub
Function primeStatus(a As Integer) As Boolean
Dim i As Integer
Dim j As Integer
For i = 2 To a - 1
If a Mod i = 0 Then
primeStatus = False
Exit Function
End If
Next i
primeStatus = True
End Function
Private Sub Command1_Click()
Dim i As Integer
'Dim j As Integer
For i = 500 To 1000
If i Mod 2 = 0 Then
If primeStatus(i \ 2) Then
Print i;
End If
End If
Next i
End Sub
captainivy 2003-12-24
其实也不难吗
有了判断素数的函数就好办了
daisy8675 2003-12-24
要驗証了﹐就沒有所謂的猜想了。
rainstormmaster 2003-12-24
同意楼上
一个判断数值是否为素数的Function：
Function PrimeStatus(TestVal As Long) As Boolean
Dim i As Long
Dim Lim As Integer
PrimeStatus = True
Lim = Sqr(TestVal)
For i = 2 To Lim
If TestVal Mod i = 0 Then
PrimeStatus = False
Exit For
End If
Next
End Function
如果要产生素数数组可以这样：
Function arrPrime1(ByVal num As Long) As Long()
Dim i As Long
Dim k As Long
Dim arrPrime() As Long
k = 0
For i = 2 To num
If PrimeStatus(i) = True Then
ReDim Preserve arrPrime(k)
arrPrime(k) = i
k = k + 1
End If
Next
arrPrime1 = arrPrime
End Function
一个判断数值是否为素数的Function：
Function PrimeStatus(TestVal As Long) As Boolean
Dim i As Long
Dim Lim As Integer
PrimeStatus = True
Lim = Sqr(TestVal)
For i = 2 To Lim
If TestVal Mod i = 0 Then
PrimeStatus = False
Exit For
End If
Next
End Function
如果要产生素数数组可以这样：
Function arrPrime1(ByVal num As Long) As Long()
Dim i As Long
Dim k As Long
Dim arrPrime() As Long
k = 0
For i = 2 To num
If PrimeStatus(i) = True Then
ReDim Preserve arrPrime(k)
arrPrime(k) = i
k = k + 1
End If
Next
arrPrime1 = arrPrime
End Function
pigsanddogs 2003-12-24
从效率上看。 lazygod() 是最快的
不过找素数可以用筛选法，另外建立个500-1000的偶数数组。 然后将素数组合成偶数。
不过找素数可以用筛选法，另外建立个500-1000的偶数数组。 然后将素数组合成偶数。
lazygod 2003-12-24
把1000以下的素数找出来，保存到一个数组。看500-1000的数是由数组里的哪两个数之和
liyan010 2003-12-24
告诉我你的email,我发给你个例子,以前作过的!
看了保你豁然开朗
看了保你豁然开朗
ljlfromjj 2003-12-24
只能被1和自己整除的就是素素。
jhzhou882 2003-12-24
Private Sub Command5_Click()
Dim iloop As Integer
Dim jloop As Integer
Dim kloop As Integer
Dim flag1 As Boolean
Dim flag2 As Boolean
For iloop = 500 To 1000 Step 2
For jloop = 3 To iloop Step 2
flag1 = True
For kloop = 2 To jloop - 1
If (jloop Mod kloop) = 0 Then
flag1 = False
'Exit For
End If
Next kloop
If flag1 = True Then
flag2 = True
For kloop = 2 To iloop - jloop - 1
If ((iloop - jloop) Mod kloop) = 0 Then
flag2 = False
'Exit For
End If
Next kloop
If flag2 = True Then
Debug.Print jloop & " " & iloop - jloop
End If
End If
If flag2 = True Then
Exit For
End If
Next jloop
Next iloop
End Sub
Dim iloop As Integer
Dim jloop As Integer
Dim kloop As Integer
Dim flag1 As Boolean
Dim flag2 As Boolean
For iloop = 500 To 1000 Step 2
For jloop = 3 To iloop Step 2
flag1 = True
For kloop = 2 To jloop - 1
If (jloop Mod kloop) = 0 Then
flag1 = False
'Exit For
End If
Next kloop
If flag1 = True Then
flag2 = True
For kloop = 2 To iloop - jloop - 1
If ((iloop - jloop) Mod kloop) = 0 Then
flag2 = False
'Exit For
End If
Next kloop
If flag2 = True Then
Debug.Print jloop & " " & iloop - jloop
End If
End If
If flag2 = True Then
Exit For
End If
Next jloop
Next iloop
End Sub
xuchuang 2003-12-24
Private Sub Command3_Click()
Dim i As Integer
Dim j As Integer
For i = 500 To 1000
For j = 3 To i / 2 Step 2
If s(j) = True Then
If s(i - j) = True Then
Debug.Print j, i - j
Exit For
End If
End If
Next
Next
End Sub
Private Function s(a As Integer) As Boolean
Dim i As Integer
Dim j As Integer
Dim k As Integer
If a = 3 Then
s = True
Exit Function
End If
If a = 2 Then
s = True
Exit Function
End If
k = a / 2
If (a Mod 2) = 0 Then
s = False
Exit Function
End If
For i = 3 To k Step 2
If (CInt(a / i)) * i = a Then
s = False
Exit Function
End If
Next
s = True
End Function
Dim i As Integer
Dim j As Integer
For i = 500 To 1000
For j = 3 To i / 2 Step 2
If s(j) = True Then
If s(i - j) = True Then
Debug.Print j, i - j
Exit For
End If
End If
Next
Next
End Sub
Private Function s(a As Integer) As Boolean
Dim i As Integer
Dim j As Integer
Dim k As Integer
If a = 3 Then
s = True
Exit Function
End If
If a = 2 Then
s = True
Exit Function
End If
k = a / 2
If (a Mod 2) = 0 Then
s = False
Exit Function
End If
For i = 3 To k Step 2
If (CInt(a / i)) * i = a Then
s = False
Exit Function
End If
Next
s = True
End Function
skytears 2003-12-24
如何判断是素数
xuchuang 2003-12-24
一个循环,查找比当前值小的素数,与当前值相减,判断差是否是素数,
flyingscv 2003-12-24
for i =500 to 1000 step 2
for j= 3 to i step 2
if j 是素数 and i-j 是素数 then print i,j,i-j
for j= 3 to i step 2
if j 是素数 and i-j 是素数 then print i,j,i-j
skytears 2003-12-24
时间关系给一下源程序或给一个思路。
SnHnBn 2003-12-24
精屁极了
victorycyz 2003-12-24
循环嵌套