Len

Syntax

Assignment Variable = Len(Source String)

Overview

Find the length of a String. (not including the null terminator ) .

Parameters

Source String can be a String variable, or a Quoted String of Characters. The Source String can also be a Byte, Word, Long, Dword, Float or Array variable, in which case the value contained within the variable is used as a pointer to the start of the Source String's address in RAM. A third possibility for Source String is a label name, in which case a null terminated Quoted String of Characters is read from a Flash memory table. Assignment Variable is a user defined variable of type Bit, Byte, Word, Long, Dword, Float or Array.

Example 1

' Display the length of SourceString
  Device = 18F25K20                  ' A suitable device for Strings
  Declare Xtal = 16          ' Tell the compiler the device is operating at 16MHz
  Declare Hserial_Baud = 9600

  Dim SourceString as String * 20    ' Create a String capable of 20 characters
  Dim Length as Byte

  SourceString = "Hello World"        ' Load the source string with characters
  Length = Len(SourceString)         ' Find the length
  HRsoutLn Dec Length               ' Display the result, which will be 11

Example 2

' Display the length of a Quoted Character String
  Device = 18F25K20                  ' A suitable device for Strings
  Declare Xtal = 16          ' Tell the compiler the device is operating at 16MHz

  Dim Length as Byte

  Length = Len("Hello World")        ' Find the length
  HRsoutLn Dec Length               ' Display the result, which will be 11

Example 3

' Display the length of SourceString using a pointer to SourceString
  Device = 18F26K40                  ' A suitable device for Strings
  Declare Xtal = 16          ' Tell the compiler the device is operating at 16MHz
  Declare Hserial_Baud = 9600

  Dim SourceString as String * 20    ' Create a String capable of 20 characters
  Dim Length as Byte                  ' Display the length of SourceString
  Dim SourceString as String * 20    ' Create a String capable of 20 characters
' Create a Word variable to hold the address of SourceString
  Dim StringAddr as Word

  SourceString = "Hello World"        ' Load the source string with characters
  ' Locate the start address of SourceString in RAM
  StringAddr = AddressOf(SourceString)
  Length = Len(StringAddr)          ' Find the length
  HRsoutLn Dec Length               ' Display the result, which will be 11

View original PDF page 361

Open page in PDF

Example 4

' Display the length of a Flash memory string
  Device = 18F26K40          ' A suitable device for Strings
  Declare Xtal = 16          ' Tell the compiler the device is operating at 16MHz
  Declare Hserial_Baud = 9600

  Dim Length as Byte
'
' Create a null terminated string of characters in flash memory
'
  Dim Source As Flash = "Hello World", 0

  Length = Len(Source)      ' Find the length
  HRsoutLn Dec Length      ' Display the result, which will be 11

See also : Creating and using Strings, Creating and using Virtual Strings with

Cdata, Cdata, Left$, Mid$, Right$, Str$, ToLower, ToUpper, AddressOf.

View original PDF page 362

Open page in PDF