Glenntyson

src/glenntyson/js-data-types-lab/lab.js

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+function greet(name) {
+  return "Hello, " + name.toUpperCase() + "!";
+}
+console.log(greet("Glenn"));
+
+// What does .length do?
+// It returns the number of characters in a string (or number of elements in an array).
+
+// What does .includes() return?
+// It returns true or false depending on whether a value exists inside a string or array.
+
+// What does .slice() do?
+// It extracts part of a string or array and returns a new one without changing the original.
+
+
+function checkEvenOdd(num) {
+  return num % 2 === 0 ? "Even" : "Odd";
+}
+console.log(checkEvenOdd(4)); 
+console.log(checkEvenOdd(7)); 
+
+// What does % do?
+// The % operator (modulus) returns the remainder after division.
+
+// What does Math.random() return?
+// It returns a random decimal number between 0 (inclusive) and 1 (exclusive).
+
+// When would you use Math.floor()?
+// You use Math.floor() to round a number DOWN to the nearest whole number.
+// Commonly used with Math.random() to get random integers.
+
+function sumArray(numbers) {
+  let total = 0;
+
+  for (let i = 0; i < numbers.length; i++) {
+    total += numbers[i];
+  }
+
+  return total;
+}
+console.log(sumArray([1, 2, 3, 4])); 
+
+// How do you access an array element?
+// You use the index with square brackets.
+
+
+// What does .push() do?
+// It adds a new element to the END of an array.
+
+// Why do we use loops with arrays?
+// To go through each element one by one so we can read, modify, or process all values.
+
+
+function describePerson(person) {
+  return `${person.name} is ${person.age} years old`;
+}
+
+// What is a key-value pair?
+// It is a way to store data in objects where:
+// "key" = the name (like a label)
+// "value" = the data stored
+// "name" is the key, "John" is the value
+
+// How do you access object data?
+// You can use dot notation or bracket notation:
+// person.name
+// person["name"]
+
+// When would you use an object instead of an array?
+// When you want to store related data with labels (keys),
+// instead of just a list of values.
+
+
+
+// Step 1: Object
+const student = {
+  name: "John",
+  scores: [80, 90, 75, 100]
+};
+
+// Step 2: Function to calculate average
+function calculateAverage(scores) {
+  let total = 0;
+
+  for (let i = 0; i < scores.length; i++) {
+    total += scores[i];
+  }
+
+  return total / scores.length;
+}
+
+// Step 3: Function to determine grade
+function getGrade(avg) {
+  if (avg >= 90) return "A";
+  else if (avg >= 80) return "B";
+  else if (avg >= 70) return "C";
+  else if (avg >= 60) return "D";
+  else return "F";
+}
+
+// Step 4: Run program
+const average = calculateAverage(student.scores);
+const grade = getGrade(average);
+
+// Step 5: Output
+console.log(`Name: ${student.name}`);
+console.log(`Average: ${Math.round(average)}`);
+console.log(`Grade: ${grade}`);
+
+
+// Reflection
+
+// Which data type felt easiest?
+// Strings were easiest because they are just text.
+
+// Which one was most confusing?
+// Objects were a little confusing because of keys and how to access them.
+
+// How do arrays and objects differ?
+// Arrays are lists.
+// Objects store data with labels (keys)..
+//
+
+// When would you use each in real applications?
+// Arrays for lists (like scores).
+// Objects for details (like a person).