Understanding Recursion with Call Stack in Python

🔁 Understanding Recursion with the Call Stack (Python) Recursion is when a function calls itself. To really understand what happens, visualize the call stack. Example: def show(n): if n == 0: return print(n) show(n - 1) print("END") show(3) Output: 3 2 1 END END END Call stack walkthrough: - show(3): prints 3, calls show(2) → Stack: [show(3)] - show(2): prints 2, calls show(1) → Stack: [show(3), show(2)] - show(1): prints 1, calls show(0) → Stack: [show(3), show(2), show(1)] - show(0): base case → return. As the stack unwinds, each function resumes and prints "END". That’s why "END" appears three times. Use cases: tree traversal (DFS), sorting (QuickSort/MergeSort), backtracking, filesystem traversal. Key takeaway: Recursion is powerful — always include a base case. #Python #Recursion #CallStack #Programming #Tech

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