Difference between revisions of "Visual Basic .net"
From ScienceZero
(→Datatypes) |
(→Datatypes) |
||
| Line 117: | Line 117: | ||
<td valign="top"><code>System.Single</code> </td> | <td valign="top"><code>System.Single</code> </td> | ||
<td valign="top">4 bytes </td> | <td valign="top">4 bytes </td> | ||
| − | <td valign="top">-3.402823E38 to -1.401298E-45 for negative values; 1.401298E-45 to | + | <td valign="top">-3.402823E38 to -1.401298E-45 for negative values; 1.401298E-45 to 3.402823E38 for positive values |
| − | + | ||
</td> | </td> | ||
</tr> | </tr> | ||
Revision as of 09:00, 27 December 2009
Contents
Graphics
Files
Reading text files line by line:
Dim f1 As Long
dim filestring as string
f1 = FreeFile()
FileOpen(f1, My.Application.Info.DirectoryPath & "\filename.txt", OpenMode.Input)
Do Until EOF(f1)
- filestring=LineInput(f1)
Loop
FileClose(f1)
Note: My.Application.Info.DirectoryPath & "\filename.txt" may be replaced by "C:\some_path\file.txt"
Writing text files line by line:
Dim f1 As Long
f1 = FreeFile()
FileOpen(f1, My.Application.Info.DirectoryPath & "\filename.txt", OpenMode.Output
Print(f1, "This is line 1")
Print(f1, "This is line 2")
FileClose(f1)
Arrays
Threading / Parallel
Loops
Conditionals
Math
RS-232
Datatypes
| Visual Basic type | .NET Runtime type | structure Storage size | Value range |
Boolean |
System.Boolean |
4 bytes | True or False |
Byte |
System.Byte |
1 byte | 0 to 255 (unsigned) |
Char |
System.Char |
2 bytes | 0 to 65535 (unsigned) |
Date |
System.DateTime |
8 bytes | January 1, 1 CE to December 31, 9999 |
Decimal |
System.Decimal |
12 bytes | +/-79,228,162,514,264,337,593,543,950,335 with no decimal point;
+/-7.9228162514264337593543950335 with 28 places to the right of the decimal; smallest non-zero number is +/-0.0000000000000000000000000001 |
Double |
System.Double |
8 bytes | -1.79769313486231E308 to -4.94065645841247E-324 for negative
values; 4.94065645841247E-324 to 1.79769313486232E308 for positive values |
Integer |
System.Int32 |
4 bytes | -2,147,483,648 to 2,147,483,647 |
Long |
System.Int64 |
8 bytes | -9,223,372,036,854,775,808 to 9,223,372,036,854,775,807 |
Object |
System.Object (class) |
4 bytes | Any type can be stored in a variable of type Object |
Short |
System.Int16 |
2 bytes | -32,768 to 32,767 |
Single |
System.Single |
4 bytes | -3.402823E38 to -1.401298E-45 for negative values; 1.401298E-45 to 3.402823E38 for positive values |
String |
System.String (class) |
10 bytes + (2 * string length) | 0 to approximately two billion Unicode characters |
| User-Defined Type (structure) | (inherits from System.ValueType) |
Sum of the sizes of its members | Each member of the structure has a range determined by its data type and independent
of the ranges of the other members |
