Data commit

Task/Queue-Definition/Tcl/queue-definition-1.tcl

@@ -0,0 +1,31 @@
+proc push {stackvar value} {
+    upvar 1 $stackvar stack
+    lappend stack $value
+}
+proc pop {stackvar} {
+    upvar 1 $stackvar stack
+    set value [lindex $stack 0]
+    set stack [lrange $stack 1 end]
+    return $value
+}
+proc size {stackvar} {
+    upvar 1 $stackvar stack
+    llength $stack
+}
+proc empty {stackvar} {
+    upvar 1 $stackvar stack
+    expr {[size stack] == 0}
+}
+proc peek {stackvar} {
+    upvar 1 $stackvar stack
+    lindex $stack 0
+}
+
+set Q [list]
+empty Q ;# ==> 1 (true)
+push Q foo
+empty Q ;# ==> 0 (false)
+push Q bar
+peek Q ;# ==> foo
+pop Q ;# ==> foo
+peek Q ;# ==> bar

Task/Queue-Definition/Tcl/queue-definition-2.tcl

@@ -0,0 +1,10 @@
+package require struct::queue
+struct::queue Q
+Q size ;# ==> 0
+Q put a b c d e
+Q size ;# ==> 5
+Q peek ;# ==> a
+Q get ;# ==> a
+Q peek ;# ==> b
+Q pop 4 ;# ==> b c d e
+Q size ;# ==> 0