add memory and time efficient stack data structure to store heterogeneous data with all functionalities

[sathvikareddykadukuntla168]

hey,I want to add memory and time efficient stack data structure to store heterogeneous data (like ex: int or char or float in same stack) with all functionalitiesin of stack in c++ ; Assign me this issue; I am very good at dsa and can contribute to this issue as a part of GSSOC'21