Arrays are used to store multiple values in a single variable.
Each value is called an element, and each element has a numeric position in the array, known as its index.
Arrays are zero-indexed, meaning the first element is at index 0, the second at index 1, and so on.
Arrays can contain any data type, including numbers, strings, and objects.
const arr1 = [2, 4, 6]; array
arr1[0]; element at index 0 → 2
arr1[1]; element at index 1 → 4
arr1[2]; element at index 2 → 6
arr1[3]; element at index 3 → undefined index not found
Numbers are used to represent both integer and floating-point values.
Numbers are most commonly expressed in literal forms like 255 or 3.14159 ↴
let num1 = 5; → number
let num2 = 2.5; → number
let num3 = num1 + num2;
console.log(num3); returns ↴
7.5 → number
Find maximum number in an array using a for loop
for loop repeatedly executes a block of code until a specified condition evaluates to false.
The loop runs a block of code a set number of times, defined by an initialization, a condition, and an increment.
for (let x = 0; x < 4; x++) {
console.log(x);
}
Loop variable x is initialized to 0
Condition x < 4 is checked before each iteration.
The loop will continue to run as long as x is less than 4
The loop repeatedly executes a block of code 4 times, from 0 to 3
For each iteration of the loop, the current value of x is printed to the console.
After each iteration, x is incremented by 1 x++
When x reaches 4 the condition evaluates to false, terminating the loop.
0
1
2
3 → printed to console
Initialize an array from which to find the maximum number.
const array1 = [5, 4, 6, 8, 7]; → user input
Define a function findMaxNumber to find maximum number.
function findMaxNumber(arr) {}
The function takes an array as input arr and returns the number with the highest value found in that array.
Start with the first element as the maximum.
let max = arr[0] max
Iterate through arr starting from the second element.
for (let x = 1; x < arr.length; x++) {}
Check if current element arr[x] is greater than the current maximum max
if (arr[x] > max) {}
Update max if the condition is true.
max = arr[x]
After the loop completes, return the maximum value found.
return max
Call the function with ↴
findMaxNumber(array1);
Find the maximum number in an array.
arr = [5, 4, 6, 8, 7]
Loop through each number in the array.
for (let x = 1; x < arr.length; x++) {}
max = 5 start with first element as the maximum.
arr[x] = 4 start from second element.
arr[x] > max
Iteration ↴
1 4 > 5 false max = 5
2 6 > 5 true max = 5 max updated
3 8 > 6 true max = 8 max updated
4 7 > 8 false max = 8
Once the loop has completed the maximum number 8 is returned.
Find the maximum number in an array.
const array1 = [5, 4, 6, 8, 7];
function findMaxNumber(arr) {
let max = arr[0];
for (let x = 1; x < arr.length; x++) {
if (arr[x] > max) {
max = arr[x];
}
}
return max;
}
call function
findMaxNumber(array1); returns ↴
8
Alternative using built-in Math.max() method.
const arr = [5, 4, 6, 8, 7]; numbers only
Math.max(...arr); returns ↴
8