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 the minimum & 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 findMinMax to find maximum number.
function findMinMax(arr) {}
The function takes an array as input arr and returns an array representing the minimum and maximum values found in that array.
Set initial min and max to the first element of the array.
let min = arr[0] min
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]
Check if current element arr[x] is less than the current minimum min
if (arr[x] < min) {}
Update min if the condition is true.
min = arr[x]
After the loop completes, return the array containing the min and max values.
return [min, max]
Call the function with ↴
findMinMax(array1);
Find the maximum number in an array.
const array1 = [5, 4, 6, 8, 7];
function findMinMax(arr) {
let min = arr[0];
let max = arr[0];
for (let x = 1; x < arr.length; x++) {
if (arr[x] > max) {
max = arr[x];
}
if (arr[x] < min) {
min = arr[x];
}
}
return [min, max];
}
call function
findMinMax(array1); returns ↴
[4, 8] → array
Alternative using built-in Math.min() and Math.max() methods.
const array2 = [5, 4, 6, 8, 7]; numbers only
function findMinMax2(arr) {
let min = Math.min(...arr);
let max = Math.max(...arr);
return [min, max];
}
call function
findMinMax2(array2); returns ↴
[4, 8] → array