Tcl Programming Examples

ns2 code for point to point network for duplex link

tcl

set ns [new Simulator]
set nf [open lab1.nam w] /* open a nam trace file in write mode */
$ns namtrace-all $nf /* nf – nam file */
set tf [open lab1.tr w] /* tf- trace file */
$ns trace-all $tf
proc finish { } { /* provide space b/w proc and finish and all are in small case */ global ns nf tf
$ns flush-trace /* clears trace file contents */ close $nf
close $tf
exec nam lab1.nam & exit 0
}
set n0 [$ns node] /* creates 4 nodes */ set n1 [$ns node]
set n2 [$ns node] set n3 [$ns node]
$ns duplex-link $n0 $n2 200Mb 10ms DropTail /*Letter M is capital Mb*/
$ns duplex-link $n1 $n2 100Mb 5ms DropTail /*D and T are capital*/
$ns duplex-link $n2 $n3 1Mb 1000ms DropTail
$ns queue-limit $n0 $n2 10
$ns queue-limit $n1 $n2 10
set udp0 [new Agent/UDP] /* Letters A,U,D and P are capital */
$ns attach-agent $n0 $udp0
set cbr0 [new Application/Traffic/CBR] /* A,T,C,B and R are capital*/
$cbr0 set packetSize_ 500 /*S is capital, space after underscore*/
$cbr0 set interval_ 0.005
$cbr0 attach-agent $udp0
set udp1 [new Agent/UDP]
$ns attach-agent $n1 $udp1
set cbr1 [new Application/Traffic/CBR]
$cbr1 attach-agent $udp1
set udp2 [new Agent/UDP]
$ns attach-agent $n2 $udp2
set cbr2 [new Application/Traffic/CBR]
$cbr2 attach-agent $udp2
set null0 [new Agent/Null] /* A and N are capital */
$ns attach-agent $n3 $null0
$ns connect $udp0 $null0
$ns connect $udp1 $null0
$ns at 0.1 "$cbr0 start"
$ns at 0.2 "$cbr1 start"
$ns at 1.0 "finish"
$ns run

Abch

tcl

#!/usr/bin/tclsh

set a 100

#check the boolean condition 
if {$a < 20 } {
   #if condition is true then print the following 
   puts "a is less than 20"
} else {
   #if condition is false then print the following 
   puts "a is not less than 20"
}
puts "value of a is : $a"

Execute Tcl Online

tcl

proc SteinsGCD { u v } {
    #begin with simple cases
    if { $u == $v } { return $u }
    if { $u == 0 } { return $v }
    if { $v == 0 } { return $u } 
    
    #looking for factors of 2, u is even
    if { (~( $u )) & 1 } { 
    #v is odd
    if { $v & 1 } { return [SteinsGCD [expr $u >> 1] $v ] } } 
    #both u and v are even
    if { ((~( $u )) & 1) & ((~( $u )) & 1)} { return [expr [ SteinsGCD [expr $u >> 1] [expr $v >> 1 ] ] <<1]  }
    
    #u is odd, v is even
    if { (~( $v )) & 1 } {
        return [SteinsGCD $u [expr $v >> 1] ]
    } 
    #reduce larger argument
    if {  $u > $v } { return [SteinsGCD  [expr [ expr $u - $v]>>1] $v] }
    
    return [SteinsGCD  [expr [ expr $v - $u] >> 1] $u] 
    
}

puts "First Number\t Second Number\t GCD"
puts "------------\t -------------\t ---"
for { set x 0 } { $x < 100 } { incr x } {
set q [expr int([expr rand() * 100])]
set w [expr int([expr rand() * 100])]
set a [SteinsGCD $q $w]
puts "$q\t\t$w\t\t$a"
}

switches command example

tcl

#!/usr/bin/tclsh

regexp -nocase -line -- {([A-Z]*.([A-Z]*))} "Tcl \nTutorial" a b 
puts "Full Match: $a"
puts "Sub Match1: $b"
regexp -nocase -start 4 -line -- {([A-Z]*.([A-Z]*))} "Tcl \nTutorial" a b  
puts "Full Match: $a"
puts "Sub Match1: $b"

switches command

tcl

#!/usr/bin/tclsh

regexp -nocase {([A-Z]*.([A-Z]*))} "Tcl Tutorial" a b c  
puts "Full Match: $a"
puts "Sub Match1: $b"
puts "Sub Match2: $c"

modified pattern

tcl

#!/usr/bin/tclsh

regexp {([A-Z,a-z]*.([A-Z,a-z]*))} "Tcl Tutorial" a b c  
puts "Full Match: $a"
puts "Sub Match1: $b"
puts "Sub Match2: $c"

multiple pattterns

tcl

#!/usr/bin/tclsh

regexp {([A-Z,a-z]*).([A-Z,a-z]*)} "Tcl Tutorial" a b c  
puts "Full Match: $a"
puts "Sub Match1: $b"
puts "Sub Match2: $c"

simple regular expression

tcl

#!/usr/bin/tclsh

regexp {([A-Z,a-z]*)} "Tcl Tutorial" a b 
puts "Full Match: $a"
puts "Sub Match1: $b"

math function

tcl

#!/usr/bin/tclsh

namespace import ::tcl::mathfunc::*
puts [tan 10]
puts [pow 10 2]
puts [ceil 10.34]
puts [hypot 10 20]
puts [srand 45]
puts [log 10]
puts [srand 45]

custom error handling

tcl

#!/usr/bin/tclsh

catch {set file [open myNonexistingfile.txt]} result
puts "ErrorMsg: $result"
puts "ErrorCode: $errorCode"
puts "ErrorInfo:\n$errorInfo\n"

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