Logic Building/Phase 3 - Level 3: Pattern Recursion/Program

Character Patterns Recursively

Print character patterns (A, AB, ABC...) recursively.

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Logic Building
def print_chars(n, current=0):
    # Base case
    if current >= n:
        return
    
    # Print character
    print(chr(65 + current), end="")  # 65 is 'A'
    # Recurse
    print_chars(n, current + 1)

def print_pattern(n, row=1):
    # Base case
    if row > n:
        return
    
    # Print row
    print_chars(row)
    print()
    # Recurse
    print_pattern(n, row + 1)

# Test
n = int(input("Enter rows: "))
print_pattern(n)

Output

Enter rows: 4
A
AB
ABC
ABCD

Use helper to print characters, main for rows.

Key Concepts:

  • Helper prints A to A+n-1
  • Main function prints rows
  • Recursive structure
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