• 3.9 Algorithms - Syntax Terrors
• What is an Algorithm?
  • Key Points
  • JavaScript
  • Python
• Finding the Maximum Value
  • Key Points
  • JavaScript
  • Python
• Examples of Existing Algorithms
  • Key Points
• Why Use Existing Algorithms?
  • Key Points
• Try It Yourself: Find the Maximum
  • Key Points
  • Try It Yourself (JavaScript)
  • Try It Yourself (Python)

3.9 Algorithms - Syntax Terrors

JavaScript Algorithms Homework Python Algorithms Homework

What is an Algorithm?

Key Points

• An algorithm is a set of steps to solve a problem.

• There are often multiple algorithms for the same task.

• Algorithms can be created from scratch or adapted from existing ones.

JavaScript

// Example: Find the sum of numbers in an array
let numbers = [1, 2, 3, 4];
let sum = 0;
for (let i = 0; i < numbers.length; i++) {
    sum += numbers[i];
}
console.log(sum);


          

In JavaScript, an algorithm is a clear sequence of steps that solves a specific problem.

• Algorithms can be written using loops, conditionals, and functions.
• Different programmers might use different approaches for the same task.

This example adds up all the numbers in an array.

Python

# Example: Find the sum of numbers in a list
numbers = [1, 2, 3, 4]
total = 0
for num in numbers:
    total += num
print(total)


          

In Python, an algorithm is just a set of instructions you write to solve a problem.

• You can use loops, conditionals, and functions to build algorithms for all kinds of tasks.
• There are usually many ways to solve the same problem.

This example adds up all the numbers in a list.

Finding the Maximum Value

Key Points

• Use a loop to compare each value.

• Keep track of the largest value found so far.

• Works in both JavaScript and Python.

JavaScript

let numbers = [5, 3, 9, 1];
let max = numbers[0];
for (let i = 1; i < numbers.length; i++) {
    if (numbers[i] > max) {
        max = numbers[i];
    }
}
console.log(max);


          

This algorithm starts by assuming the first number is the largest.

• It loops through the rest of the array, updating the largest number whenever it finds a bigger one.
• At the end, it prints the largest value.

Python

numbers = [5, 3, 9, 1]
max_num = numbers[0]
for num in numbers[1:]:
    if num > max_num:
        max_num = num
print(max_num)


          

This algorithm starts by assuming the first number is the largest.

• It loops through the rest of the list, updating the largest number whenever it finds a bigger one.
• At the end, it prints the largest value.

Examples of Existing Algorithms

Key Points

• Finding the maximum or minimum value in a list

• Calculating sums or averages

• Sorting a list

• Finding a path through a maze

• Compressing data

Why Use Existing Algorithms?

Key Points

• Saves development and testing time

• Reduces bugs by using proven solutions

• Makes debugging easier

• Always cite algorithms you use from others

Try It Yourself: Find the Maximum

Key Points

• Practice using an algorithm to solve a problem

• Use a loop to find the largest number in a list

Try It Yourself (JavaScript)

Write code that prints the largest number in the array. The expected output should be '9'.

Try It Yourself (Python)

Write code that prints the largest number in the list. The expected output should be '9'.