[急]帮忙解一道VB编程题

用循环显示结果，每项数据前交替出现正负号。
比如输入7
出来的结果
+1
-1 +12
+1 -12 +123
-1 +12 -123 +1234
+1 -12 +123 -1234 +12345
-1 +12 -123 +1234 -12345 +123456
+1 -12 +123 -1234 +12345 -123456 +1234567
这个题目怎么写代码，大家帮帮忙！！谢谢！！
刚刚没问清楚，如果像下面的该怎么填？？
Private Sub Command1_Click()
Dim s As Long, i%, j%, n%, fh%, str1 As String
n = Val(Text1)
For i = __(1)
s = 0
fh = IIf(i Mod 2 = 0, 1, -1) ' 控制 i 行第一项数据的正负号
For j = 1 To i
fh = (2) ' 控制 j 列上数据的正负号
s = ___ (3) _ ' 产生 j 列上的数据
str1 = Trim(Str(s))
If fh = -1 Then ' 输出 j 列上的数据
______(4)______
Else
Picture1.Print " +"; str1;
End If
Next j
_____(5)____
Next i
End Sub

Private Sub Command1_Click()
Dim s As String, b As Boolean, c As Boolean
For i = 1 To 7
c = Not c
b = c
For j = 1 To i
s = ""
For k = 1 To j
s = s & k
Next
Print IIf(b, "+", "-") & s & " ";
b = Not b
Next
Print
Next
End Sub

===================================
Private Sub Command1_Click()
Dim s As Long, i%, j%, n%, fh%, str1 As String
n = Val(Text1)
For i = 1 To 7
s = 0
fh = IIf(i Mod 2 = 0, 1, -1) ' 控制 i 行第一项数据的正负号
For j = 1 To i
fh = IIf(fh = -1, 1, -1) ' 控制 j 列上数据的正负号
s = s * 10 + j ' 产生 j 列上的数据
str1 = Trim(Str(s))
If fh = -1 Then ' 输出 j 列上的数据
Picture1.Print " -"; str1;
Else
Picture1.Print " +"; str1;
End If
Next j
Picture1.Print
Next i
End Sub

1: 1 To 7
2: IIf(fh = -1, 1, -1)
3: s * 10 + j