What do you understand by 'set off' and 'counter-claim' under the Civil Procedure Code, 1908? What is the effect of set-off ?

Set-off Order VIII, Rule 6 of Civil Procedure Code, 1908 deals with set-off which is a reciprocal acquittal of debts between the plaintiff and defendant. It has the effect of extinguishing the plaintiff's claim to the extent of the amount claimed by the defendant as a counter claim. Under Order VIII, Rule 6 of Civil Procedure Code, 1908 where in a suit for the recovery of money the defendant claims to set off against the plaintiff’s demand any ascertained sum of money legally recoverable by him from the plaintiff not exceeding the pecuniary jurisdiction of the Court and where both parties fill the same character as in the plaintiff is suit, the defendant may, at the first hearing of the suit, but not afterwards unless permitted by the Court, present a written statement containing the particulars of the debt sought to be set-off. Counter-claim A defendant in a suit may, in addition to his right of pleading a set-off under Rule 6, set up by way of counterclaim against the claim of the plaintiff, any right or claim in respect of a cause of action accruing to the defendant against the plaintiff either before or after the filling of the suit but before the defendant has delivered his defence or before the time limited for delivering his defence has expired, whether such counterclaim is in the nature of claim for damages or not. Such counter-claim must be within the pecuniary jurisdiction of the Court. (Order VIII, Rule 6A). Effect of Set-off The written statement shall have the same effect as a plaint in a cross-suit so as to enable the Court to pronounce a final judgement in respect both of the original claim and of the set-off, but this shall not affect the lien, upon the amount decreed, of any pleader in respect of the costs payable to him under the decree.