2.1 Introduction Specifications A stack is a data structure in which all insertions and 3 deletions of entries are made at one end, called the top of the stack. The last entry which is Top inserted is the first one that will 2 be removed 3 Characteristic. Last In first outA stack is a data structure in which all insertions and deletions of entries are made at one end, called the top of the stack. The last entry which is inserted is the first one that will be removed. 2.1 Introduction Specifications 2 3 4 1 4 3 Top 4 3 3 Characteristic: Last In First Out