cs110 lecture 3

• Programming concepts


  Abstract programming concepts, including: the four basic control structures, plus interaction; Combining them to make an algorithm; Variables; Two basic data types
• Determining if a year is a leap year


  1. Ask the person for a four-digit year

  2. Write the Year in your notebook

  3. Decide whether or not YearIsLeapYear

  4. If YearIsLeapYear, say "Year is a leap year"

  5. Otherwise, say "Year is not a leap year"
• Leap year computer algorithm

  1. Prompt user for four-digit year

  2. Input Year

  3. Compute YearIsLeapYear

  4. If YearIsLeapYear is true, write "Year is a leap year"

  5. Otherwise, write "Year is not a leap year"
• Variable declaration


  Tells the computer what the variable will be called and what type of data the variable will store
• Data types


  • int (integers)
  • string (sequences of characters)
• Code editors


  • Lightweight and fast
  • Free or very affordable
  • Easy to learn
  • Can be extended to have IDE-like features with plug-ins
• IDEs


  • Ready to use "out of the box"
  • Works particularly well for large projects
• Popular free IDEs


  • Visual Studio Code
  • MS Visual Studio Community
  • Code Blocks
  • Repl.it
• Programming errors


  • Syntax Errors
  • Runtime Errors
  • Logic Errors
• Syntax Errors


  Typos in your code that the compiler detects, preventing the code from compiling
• Runtime Errors


  Bugs that aren't detected by the compiler and cause the program to terminate while running
• Logic Errors


  Flaws in the logic underlying the algorithm, resulting in unexpected results
• Programming style and documentation

  • Appropriate Comments
  • Proper Indentation and Spacing Lines
  • Block Styles
• Programming life cycle


  1. Problem-solving

  2. Implementation

  3. Maintenance
• Problem-solving phase


  1. Analyze the problem and specify what the solution must do

  2. Develop a general solution (algorithm) to solve the problem

  3. Verify that your solution really solves the problem
• Input data


  Data from outside the program
• Formula constants


  Values used in the program
• Computed values


  Values produced by the program
• Output results


  Results written to a file or screen by the program
• Implementation phase: Write code

  1. Translating your algorithm into a programming language (coding)

  2. Using code, documentation, and a compiler to translate the program into machine language
• Implementation phase: Test


  1. Running the program to see if it produces correct results

  2. Debugging to find and fix errors
• Maintenance phase


  1. Using and modifying the program to meet changing requirements or correct errors

  2. Rewriting code if necessary
• The programming life cycle has three main phases: problem-solving, implementation, and maintenance
• Algorithm to determine an employee's weekly wages

  1. Get the employee's hourly payRate

  2. Get the hours worked this week

  3. Calculate regular wages

  4. Calculate overtime wages (if any)

  5. Add regular wages to overtime wages (if any) to determine total wages for the week
• Formula constants


  • Normal work hours (40.0)
  • Overtime pay rate factor (1.5)
• Input data


  • Hourly payRate
  • Hours worked
• Computed values


  • Overtime hours worked
  • Wages
• Problem-solving techniques include asking questions, looking for familiar things, solving by analogy, and using means-ends analysis