Notes

Understanding Procedures

  • A procedure is a set of instructions that is given a name which takes in parameters to return values
    • also called methods and functions
    • Sequencing, selection, and iteration are procedures
  • Parameters are independent variables used in the procedure to produce a result
    • Allows procredure to run without knowing the specific input values.

  • As you an see, this procedure is named “multiply” its parameters are “x” and “y” and returns “The product of 5 times 3 is 15

Calling Procedures

  • You call a procedure by putting the name of ot follwed by paranthesis with the parameters.
    • Ex: def math(x)

Determining the result of a procedure

  • Follow the code line by line to see what eaach line does
  • Use syntax to determine
    • function parameters and retunr value and statements.

  • to return the values you write “return” then the expression you want to return that has been defined.

  • As you can see this code originally did not have return statement

  • After debugging it with the return statement “return result” we can see the actual output of the function.

Managing Complexity

Modularity

  • the practice of breaking a complex program into smaller, independent parts or modules that can be used and reused in different parts of the program
    • Ex: assert “hypotenuse(3, 4) == hypotenuse_abstracted(3, 4) == 5”
      • They would have the same result.

        Abstraction

  • the practice of hiding the details of how a particular code or system works and exposing only the essential features or functions that are necessary for other parts of the program to use

    Duplication

  • having multiple duplicate code blocks, often decreasing readability and efficiency

    Logic

  • the sequence of steps and operations that a computer follows to execute a program, including the specific instructions and decision-making processes built into the code

Developing Procedures

  • Parameters store variables and arguments

  • Call functions with procedure names (syntax in javascript and python)

  • Procedure name: the name that was given to a function
  • Arguments provied info to a functio and are usually defined outside of the function then imported into a function with parameters.

Python:

def function(a,b): # function is defined
  print(a+b) # prints output of variables

function(1,2) # one instance that it can be used
function(2,3) # another instance

3
5
  • defines the function with the parameters then prints their sum
    • 1 + 2 is 3
    • 2 + 3 is 5

      JavaScript:

function Function(a,b) {
  return a + b;
}

Function(1,2)
Function(2,3)

3
5
  • Calls the function with the parameters then adds them together
    • 1 + 2 is 3
    • 2 + 3 is 5

More Parameters

  • someetimes parameters will provide input to the function

  • This function provides 2 parameters and uses them as inputes and calling the function compares the 2 numbers.

Hacks

3.12

Procedure and Parameter

  • Procedure: In an algorithm, it completes a certain task
    • must be called to function
    • Will take in parameters and will output values.
  • Parameters: Variables that are usually used within procedures.

Quiz (3/3)

Return Values and Output Parameters

  • Return Values: The result of the procedure once it is run
  • Output Parameters: variables that are used within procedures that can lead to a certain output.

Code a square root procedure

3.13

Why is abstracting program logic into seperate modular functions effective?

  • Abstracting a program into seperate modualr functions allows the coder to understand how each part of the code works. If it is a long, complex code it is better to break it down into a greater amount of more simpler modular functions so the program overall is simpler to read.

Procedure that uses other sub-procedures + explaination

  • This program contains three sub-procedures: main(), print_foods(), and add_food().
    • The main() procedure serves as the entry point for the program, and it calls the other two sub-procedures to perform specific tasks.
    • The print_foods() procedure takes a list of foods as an argument and prints out each item in the list, while the add_food() procedure prompts the user for a new food to add to the list and then returns that new food.
  • As you can see, I inputted “Falafel” as a food and it added falafel to the list of food.

Add another layer of abstraction to the word counter

Procedure Names and Arguments

  • Procedure names: the names given to a method to produce an output
  • Arguments: the data that is inputted into the function for example:

Code of Procedures, Arguments, and Parameters (interactive with HTML and JavaScript)

  • Here is an example of a calculator that uses arguments and parameters with Script and HTML.

  • Write an expression using “+, -, /, or *” between TWO numbers and press calculate
  • For example: 3*3 would output 9.

<!DOCTYPE html>

Calculator

Calculator