#Create Simulator
set ns [new Simulator]
#Open trace and NAM trace file
set ntrace [open prog4.tr w]
$ns trace-all $ntrace
set namfile [open prog4.nam w]
$ns namtrace-all $namfile
#Finish Procedure
proc Finish {} {
global ns ntrace namfile
#Dump all trace data and close the file
$ns flush-trace
close $ntrace
close $namfile
#Execute the nam animation file
exec nam prog4.nam &
exit 0
}
#Create 3 nodes
set n0 [$ns node]
set n1 [$ns node]
set n2 [$ns node]
$ns duplex-link $n0 $n1 1Mb 10ms DropTail
$ns duplex-link $n1 $n2 1Mb 10ms DropTail
#Define the recv function for the class 'Agent/Ping'
Agent/Ping instproc recv {from rtt} {
$self instvar node_
 puts "$from received ping answer from node [$node_ 
id] with round trip time $rtt ms"
}
#Create two ping agents and attach them to n(0) and 
n(2)
set p0 [new Agent/Ping]
$ns attach-agent $n0 $p0
set p1 [new Agent/Ping]
$ns attach-agent $n2 $p1
$ns connect $p0 $p1
#Schedule events
$ns at 0.2 "$p0 send"
$ns at 0.4 "$p1 send"
$ns at 1.2 "$p0 send"
$ns at 1.7 "$p1 send"
$ns at 1.8 "Finish"
#Run the Simulation
$ns run

Tool Command Language(TCL) online compiler

Write, Run & Share TCL code online using OneCompiler's TCL online compiler for free. It's one of the robust, feature-rich online compilers for TCL language, running the latest TCL version 8.6. Getting started with the OneCompiler's TCL editor is easy and fast. The editor shows sample boilerplate code when you choose language as TCL and start coding.

Taking inputs (stdin)

OneCompiler's TCL online editor supports stdin and users can give inputs to programs using the STDIN textbox under the I/O tab. Following is a sample TCL program which takes name as input and prints hello message with your name.

set name [gets stdin]
puts "Hello $name"

About TCL

Tool Command Language(TCL) is a general purpose scripting language which is commonly used for GUIs and for testing. Everything is by default string in TCL. It was created by John Osterhout in 1989.

Syntax help

Variables

Variable is a identifier which is used to hold the value. set is used to create variables.

Examples

set name onecompiler

Loops

1. If-Else:

When ever you want to perform a set of operations based on a condition IF-ELSE is used.

if(conditional-expression) {
   #code
} else {
   #code
}

You can also use if-else for nested Ifs and If-Else-If ladder when multiple conditions are to be performed on a single variable.

2. Switch:

Switch is an alternative to If-Else-If ladder.

switch(conditional-expression) {    
value1 {     
 # code
}    
value1 {     
 # code
}    
...
default {
# code
}

3. For:

For loop is used to iterate a set of statements based on a condition.

for{start}{test}{next}{  
  # code  
}

4. While:

While is also used to iterate a set of statements based on a condition. Usually while is preferred when number of iterations are not known in advance.

while(condition) {  
 # code 
}

Arrays

Array is a collection of similar data which is stored in continuous memory addresses. Array values can be fetched using index. Index starts from 0 to size-1.

Syntax

set ArrayName(Index) value

Procedures

Procedure is a sub-routine which contains set of statements. Uusually procedures are required when multiple calls are made to same set of statements. Procedures increases re-usuability and modularity.

Syntax

proc procedureName {arguments} {
   # code
}