added all the basic folder files

Author: DadaNanjesha

basics/control_structures.md

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+# Python Control Structures: Master Program Flow🚦🔀  
+
+Control structures determine how your Python programs make decisions and repeat actions. They're the backbone of programming logic!  
+
+---
+
+## 🌟 **1. Conditional Statements (Decision Making)**  
+
+Make your programs smart by executing different code blocks based on conditions.  
+
+### `if` Statement  
+```python
+age = 18
+if age >= 18:
+    print("🎉 You are an adult!")
+# Output: 🎉 You are an adult!
+```
+
+### `if-else` Statement  
+```python
+age = 16
+if age >= 18:
+    print("🍻 Cheers! You can vote.")
+else:
+    print("📚 Focus on school!") 
+# Output: 📚 Focus on school!
+```
+
+### `if-elif-else` Ladder  
+```python
+score = 87
+
+if score >= 90:
+    grade = 'A'
+elif score >= 80:
+    grade = 'B'  # ← This executes
+elif score >= 70:
+    grade = 'C'
+else:
+    grade = 'Need improvement'
+
+print(f"📊 Your grade: {grade}") 
+# Output: 📊 Your grade: B
+```
+
+### Nested `if`  
+```python
+num = 15
+
+if num > 0:
+    if num % 2 == 0:
+        print("➕ Positive even number")
+    else:
+        print("➕ Positive odd number")  # ← This executes
+else:
+    print("❌ Number is not positive")
+```
+
+---
+
+## 🔄 **2. Looping Statements**  
+
+Automate repetitive tasks efficiently.  
+
+### `for` Loop  
+```python
+# Loop through a list
+fruits = ["🍎", "🍌", "🍒"]
+for fruit in fruits:
+    print(f"Fruit: {fruit}")
+
+# Using range()
+for i in range(3):          # 0, 1, 2
+    print(f"Count: {i}")
+
+for i in range(5, 8):       # 5, 6, 7
+    print(f"Number: {i}")
+
+for i in range(0, 10, 3):  # 0, 3, 6, 9
+    print(f"Step: {i}")
+```
+
+### `while` Loop  
+```python
+count = 0
+while count < 3:
+    print(f"🚀 Launch in {3-count}...")
+    count += 1
+# Output: 
+# 🚀 Launch in 3...
+# 🚀 Launch in 2...
+# 🚀 Launch in 1...
+```
+
+### Nested Loops  
+```python
+for row in range(3):
+    for col in range(2):
+        print(f"📍 Cell ({row},{col})")
+# Outputs all combinations from (0,0) to (2,1)
+```
+
+---
+
+## ⚡ **3. Loop Control Statements**  
+
+Fine-tune your loop execution.  
+
+| Statement  | Effect                          | Example Use Case              |
+|------------|---------------------------------|-------------------------------|
+| `break`    | Exits the entire loop           | Searching → exit when found   |
+| `continue` | Skips current iteration         | Skip invalid data             |
+| `pass`     | Does nothing (placeholder)      | Structure code before filling |
+
+### `break` Example  
+```python
+for num in range(10):
+    if num == 5:
+        print("🛑 Stopping at 5!")
+        break
+    print(num)  # Prints 0-4
+```
+
+### `continue` Example  
+```python
+for num in range(5):
+    if num == 2:
+        print("⏩ Skipping 2")
+        continue
+    print(num)  # Prints 0,1,3,4
+```
+
+### `pass` Example  
+```python
+for num in range(3):
+    if num == 1:
+        pass  # TODO: Add logic later
+    print(num)  # Prints 0,1,2
+```
+
+---
+
+## 🎁 **4. Special Features**  
+
+### `else` with Loops  
+Executes when loop finishes normally (no `break`):  
+```python
+for n in range(3):
+    print(n)
+else:
+    print("✅ Loop completed successfully!")
+
+# Output: 
+# 0
+# 1
+# 2
+# ✅ Loop completed successfully!
+```
+
+### Ternary Operator (One-line `if-else`)  
+```python
+age = 20
+can_vote = "Yes" if age >= 18 else "No"
+print(f"Voting eligible? {can_vote}")  # Output: Yes
+```
+
+### Walrus Operator (Python 3.8+)  
+Assign and check in one expression:  
+```python
+while (food := input("🍕 Favorite food? ")) != "quit":
+    print(f"Yummy {food}!")
+# Keeps asking until user types "quit"
+```
+
+---
+
+## 🏆 **Best Practices**  
+
+✅ **Keep conditions simple**  
+```python 
+# Good
+if is_valid and has_permission:
+    ...
+
+# Avoid
+if (x > 5 and y < 10) or (z == 0 and not flag):
+    ...
+```
+
+✅ **Limit nesting depth**  
+```python
+# Use functions instead of:
+if condition1:
+    if condition2:
+        if condition3:
+            ...
+```
+
+✅ **Choose the right loop**  
+- `for` when you know iterations  
+- `while` for dynamic conditions  
+
+✅ **Prevent infinite loops**  
+```python
+# Always have an exit condition!
+while True:
+    user_input = input("Type 'exit': ")
+    if user_input == "exit":
+        break
+```
+
+✅ **Use descriptive loop variables**  
+```python
+# Good
+for student in classroom:
+    ...
+
+# Avoid
+for x in y:
+    ...
+```
+
+---
+
+## 🧩 **Quick Reference Table**  
+
+| Structure         | Syntax Example                    | Use Case                     |
+|-------------------|-----------------------------------|------------------------------|
+| `if-else`        | `if x > 0: ... else: ...`         | Binary decisions             |
+| `elif` ladder    | `if x>90: ... elif x>80: ...`     | Multiple conditions          |
+| `for` loop       | `for item in collection: ...`     | Iterating known sequences    |
+| `while` loop     | `while condition: ...`            | Until condition changes      |
+| `break`          | `if found: break`                 | Early exit                   |
+| `continue`       | `if invalid: continue`            | Skip iteration               |
+
+---
+
+Now you're equipped to control your Python programs like a pro! 🐍💪  
+Remember: Good program flow leads to clean, efficient code. Happy coding! 💻✨