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Statement
Solution

Exercise 3.4: Pattern Printing

Use Nested Loops (a loop inside another loop) to print a right-angled triangle of stars.

Your program should:

  • Take the number of rows as input (use 5 for the standard pattern).
  • Use an Outer Loop to handle the rows (1 to N).
  • Use an Inner Loop to handle the columns. The number of stars should equal the current row number.
  • Print * without moving to a new line inside the inner loop.
  • Print a new line after the inner loop finishes.

Sample Interaction:

Input
Output
5
Enter rows: 5 * ** *** **** *****

Solution

To keep the cursor on the same line while printing, use end="" inside the print function.

# 1. Get User Input rows = int(input("Enter rows: ")) print() # Important: Force new line after input # 2. Outer loop for rows (1 to rows) for i in range(1, rows + 1): # 3. Inner loop for columns (1 to current row number) for j in range(i): print("*", end="") # 4. Move to new line after inner loop print()

Key Concepts:

  • range(1, rows + 1) ensures we get exactly N rows.
  • print("*", end="") suppresses the default newline character, allowing stars to appear side-by-side.
  • The empty print() handles the line break after each row is finished.
Python 3
Test Console
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