Tcl Hello World

puts "Hello World!"

proc try {a {b 3}} {
    puts "in Try, the a is $a"  
    set a [expr $b * 2]
    return "The a is $a and b is $b"
}

set msg [try 4]
# set msg "I am the one!"
puts $msg

set A(a) "V1"
set A(b) "V2"
set A(c) "V3"

foreach {k v} [array get A] {
    puts "key : $k ; val : $v"
}

puts [array names A]
# puts [keys $A]
puts [array get A]
puts [array size A]

array set A1 {aa 0 bb 1 cc 20}
foreach {k v} [array get A1] {
    puts "key : $k ; val : $v"
}