Lecture Notes 8/24/04 (part 2)

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Lecture Notes 8/24/04 (part 2)
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Pseudocode (review)

• Pseudocode standard which we will follow in this
  class
• - Statements are written in simple English
• - Each instruction is written on a separate
  line
• - Each set of instructions is written from
  top to bottom, with only
• one entry and one exit
• - Groups of statements may be formed into
  modules, and that
• group given a name.

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How to Write Pseudocode

• 6 basic computer operations
• receive information
• put out information
• perform arithmetic
• assign a value to a variable or memory location
• compare two variables and select one of two
  alternative actions
• repeat a group of actions

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Receive Information

• A computer generally gets information in one of
  the following ways
• From a file
• Pseudocode -gt Read
• From a keyboard
• Pseudocode -gt Get

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Receive Information

• Examples
• Get file name
• Read first line from the file
• Get number of students
• Read the names of the students from the file

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Put Out Information

• A computer generally outputs information in one
  of the three ways
• Print on a printer
• Print
• Write to a file
• Write
• Display on a monitor
• Display

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Put Out Information

• Examples
• Print Hello everyone!
• Write My first homework to hw_1.txt
• Display average_age

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Perform Arithmetic

• Either actual mathematical symbols or words can
  be used
• Multiply Length by Width to compute Area
• Area Length Width

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Perform Arithmetic

• Symbols that will be used in this class
• Addition
• Subtraction -
• Division /
• Multiplication
• Modulus
• Parentheses ()
• Also can use the words Compute and Calculate

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Example

• Write the pseudocode for calculating the average
  age of the students in our class.
• Prompt the user for number of students
• Get number of students
• Prompt for all of the ages
• Get the ages of all students
• Add all ages together to obtain Total_Age
• Divide Total_Age by the number of students
• Display the result