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🔄 Programming Loops Cheat Sheet

📋 Quick Reference​

For Loop Syntax​

Python​

for item in sequence:
    # code block

Java​

for (initialization; condition; increment) {
    // code block
}

C​

for (initialization; condition; increment) {
    // code block
}

JavaScript​

for (initialization; condition; increment) {
    // code block
}

While Loop Syntax​

Python​

while condition:
    # code block

Java​

while (condition) {
    // code block
}

C​

while (condition) {
    // code block
}

JavaScript​

while (condition) {
    // code block
}

Do-While Loop Syntax​

Java​

do {
    // code block
} while (condition);

C​

do {
    // code block
} while (condition);

🎯 Common Patterns​

Counting 1 to N​

for i in range(1, n + 1):
    print(i)

Sum of Numbers​

total = 0
for num in numbers:
    total += num

Factorial​

factorial = 1
for i in range(1, n + 1):
    factorial *= i

Reverse Number​

reverse = 0
while num > 0:
    reverse = reverse * 10 + num % 10
    num //= 10

⚡ Control Statements​

Break Statement​

for i in range(10):
    if i == 5:
        break  # Exit loop
    print(i)

Continue Statement​

for i in range(10):
    if i % 2 == 0:
        continue  # Skip iteration
    print(i)

🎪 Nested Loops​

Pattern Printing​

for i in range(n):
    for j in range(i + 1):
        print("*", end="")
    print()

Matrix Operations​

for i in range(rows):
    for j in range(cols):
        # Process matrix[i][j]
        pass

📊 Performance Tips​

Optimization Guidelines​

  • ✅ Use range() instead of list creation
  • ✅ Minimize operations inside loops
  • ✅ Consider list comprehensions for simple operations
  • ✅ Use appropriate loop types for the task

Common Pitfalls​

  • ❌ Infinite loops (missing condition update)
  • ❌ Off-by-one errors in loop bounds
  • ❌ Modifying collection while iterating
  • ❌ Unnecessary nested loops

🔍 Debugging Checklist​

  • Loop condition is correct
  • Loop variables are initialized
  • Loop body updates condition
  • No infinite loops
  • Correct loop bounds
  • Proper indentation

Last updated: Phase 3 Implementation