let arr = [];

arr.push(100);

arr.push(10);

arr.push("ali");

arr.push(false);

console.log(arr[0]);

console.log(arr);

arr.pop();

console.log(arr);

let arr1 = new Array(3);

arr1[0] = 100;

arr1[1] = 90;

arr1[2] = 80;

arr1[3] = 70;

console.log(arr1);

let arr2 = new Array(5);

for (let i = 0; i < arr2.length; i++) {

arr2[i] = Number(prompt("Enter a value"));

}

console.log(arr2);

// sum of array

let arr3 = [10, 20, 30, 40, 50];

let sum = 0;

for (let i = 0; i < arr3.length; i++) {

sum += arr3[i];

}

console.log(sum);

// max

let arr4 = [10, 2, 78, 100, 4];

let max = arr4[0];

for (let i = 0; i < arr4.length; i++) {

if (max < arr4[i]) {

max = arr4[i];

}

}

console.log(max);

// Second max

let arr5 = [10, 30, 56, 43, 29, 64, 49, 60];

let max1 = Math.max(arr5[0], arr5[1]);

let sMax = Math.min(arr5[0], arr5[1]);

for (let i = 2; i < arr5.length; i++) {

if (arr5[i] > max) {

sMax = max;

mar = arr5[i];

} else if (arr5[i] > sMax && max != arr5[i]) {

sMax = arr5[i];

}

}

console.log(sMax);

// Reverse Array with extra space

let arr6 = [10, 20, 30, 40, 50];

let temp = new Array(arr6.length);

let j = 0;

for (let i = arr6.length - 1; i >= 0; i--) {

temp[j] = arr6[i];

j++;

}

console.log(temp);

// my logic with push

let arr7 = [10, 20, 30, 40, 50];

let newArr7 = [];

for (let i = arr.length - 1; i >= 0; i--) {

mainArr7.push(arr7[i]);

}

console.log(mainArr7);

// Reverse Array with no extra space & no extra array

let arr8 = [10, 20, 30, 40, 50];

let i = 0;

let k = arr8.length - 1;

while (i !== j) {

let temp = arr8[i];

arr8[i] = arr8[j];

arr8[j] = temp;

i++;

j--;

}

console.log(arr8);

// 0s on the left and 1s on right -> two pointer theory

let arr9 = [0, 1, 0, 1, 1, 0, 0, 1, 0, 1, 0, 0];

let b = 0;

for (let i = 0; i < arr9.length; i++) {

if (arr9[i] === 0) {

let temp = arr9[b];

arr9[b] = arr9[i];

arr9[i] = temp;

b++;

}

}

console.log(arr9);

// 0s on the left and 1s on right using while loop -> two pointer theory

let arr10 = [0, 1, 0, 1, 1, 0, 0, 1, 0, 1, 0, 0];

let e = 0;

let f = 0;

while (e < arr10.length) {

if (arr10[e] === 0) {

let temp = arr10[f];

arr10[f] = arr10[e];

arr10[e] = temp;

f++;

}

e++;

}

console.log(arr10);