A stack is a linear data structure that follows the Last-In-First-Out (LIFO) principle, where the last element added is the first one to be removed. This unique characteristic makes stacks particularly useful in various applications.

Evaluation of Arithmetic Expressions

Stacks are highly effective for evaluating arithmetic expressions, especially those in postfix notation (Reverse Polish Notation). The stack allows for efficient handling of operators and operands, ensuring that the most recent operand is always available for operations¹.

Example

Consider the infix expression 2 * (4 + 3) - 5. Its equivalent postfix expression is 2 4 3 + * 5 -. The stack helps in evaluating this expression step-by-step, ensuring correct precedence and associativity¹.

Backtracking

Backtracking algorithms, such as solving mazes or puzzles, use stacks to keep track of the paths taken. When a dead-end is reached, the stack allows the algorithm to backtrack to the previous state and try a different path¹.