For loop in TCL

For loop in TCL can be achieved using the command for. It is used to execute code for multiple numbers of time.

Let’s see the syntax of for command:

for { start } { test } { next }

{

body

}

Here, start portion is used to initialise the variable. test is an expression, which will return either true or false . next is the portion to increment a variable, which has been written in the start portion.

Let’s see some examples:

1. Increment by 1

# Example for loop

for {set i 0} {$i < 3} {incr i} {

puts "Value of i is: $i"

}

Output is :

Value of i is: 0 
Value of i is: 1 
Value of i is: 2

 

2. Increment by 2

# Example increment by 2

for {set i 0} {$i < 5} {incr i 2} {

puts "Value of i is: $i"

}

Output :

Value of i is: 0
Value of i is: 2
Value of i is: 4

 

3. Loop through in reverse direction:

# Loop through in reverse direction

for {set i 5} {$i > 0} {incr i -1} {

puts "Value of i is: $i"

}

Output:

Value of i is: 5
Value of i is: 4
Value of i is: 3
Value of i is: 2
Value of i is: 1