Program Logic and Design: Comparing Selections and Loops

Selection Structures

• Single alternative selection structure
• Boolean expression: Represented by a diamond-shaped decision symbol
• If True (Yes Path): A subsequent action occurs
• If False (No Path):
  • For selection structures, the subsequent step at the bottom will still occur.

Loop Structures

• Boolean expression: Also starts with a decision symbol
• If False (No Path): The loop is not entered
• If True (Yes Path):
  • The structure within the loop is executed
  • This continues until the Boolean expression is false

Key Differences

• Selection Structure:
  • Two logical paths (True or False)
  • Paths converge at the subsequent step
• Loop Structure:
  • One logical path branch returns to the decision point

Common Logic Mistakes

• Example of a Logic Mistake:
  • Repeatedly performing steps like "not end of file, display record, input record"
  • Repetitious code can lead to missing records if the count is underestimated

Benefits of Using Loops

• Eliminates repetitiousness
• More efficient and structured
• Handles any number of records:
  • Whether it’s 5, 10, or 10 million records, the loop manages them seamlessly
• Logic and efficiency: Makes the program run smoothly by avoiding code redundancy

Conclusion

• Utilizing loops can significantly enhance the efficiency of your code by reducing redundancy
• Join the next video for an introduction to arrays and subscripts