Parsing a string using conversion specifiers

To parse a string in Tcl using conversion specifiers we will be using the scan command. The scan command parses the string in a similar manner as in the ANSI C sscanf procedure. As the scan command does not accept switches such as the regexp and regsub commands, we will proceed directly to the command. The syntax of the command is as follows:

scan string format variable variable variable…

The scan command accepts a string to parse and based on the format provided, it will convert the string. If variables are provided, they will be updated to the output of the conversions.

The scan command supports the following conversion characters:

Character	Description
d	The input string must be a decimal integer.
o	The input string must be an octal integer.
u	The input string must be a decimal integer (as in the case of d). The output is assigned to the variable as an unsigned decimal string.
s	The input substring consists of all the characters...