MnO2 +4 HCl gives MnCl2 +2H2O +Cl2 which is oxidising and reducing agent in this?

MnO₂ + 4HCl --> MnCl₂ + Cl₂ + 2H₂O

Mn is in +4 oxidation state in MnO₂ while it is in +2 Oxidation state in MnCl₂ , thus a decrease in oxidation number shows that MnO₂ undergo reduction, and so it will work as an oxidizing agent.

In HCl, Chlorine is in -1 oxidation state while it becomes 0 in Cl₂ , the increase in oxidation number shows that HCl undergoes oxidation and so it will act as a reducing agent.