Programs on Array

Implementing Queue using Array

A queue is a data structure that follows the First In First Out (FIFO) or First Come First Serve (FCFS) principle.

The first element added to the queue is the first one to be removed. This is like being in a queue to get a movie ticket. The first one in the queue gets the ticket first.

Queues can be implemented in JavaScript using either the push and shift methods or unshift and pop methods of the array object. Although this is a simple way to implement queues, it is very inefficient for large queues — because of the methods operate on arrays, the shift and unshift methods move every element in the array each time they are called.

Example of train ticket booking

const waiting_list = ["Sahil", "Bhakti", "Sakshi"];
console.log(waiting_list);
waiting_list.push("Nikita");
console.log(waiting_list);

waiting_list.shift()
console.log(waiting_list)

Output

["Sahil", "Bhakti", "Sakshi"]
>["Sahil", "Bhakti", "Sakshi". "Nikita"]

["Bhakti", "Sakshi". "Nikita"]

waiting_list.push(" ") used to add passenger name in queue. waiting_list.shift(" ") used to remove or shift name from queue.

In this program [0:Sahil, 1:Bhakti, 2:Sakshi, 3:Nikita ] this are waiting list names, this names can be added by using waiting_list.push().

After this if the ticket is confirm of index number 1:sahil then it will be automatically shift by using waiting_list.shift(),then the list will be [0:Bhakti, 1:Sakshi, 2:Nikita].

Example to find largest number from given array

const marks = [99, 50, 180, 70]
let largest = marks[0]
for (const num of marks)
{
    if(num>largest)
    {
        largest=num
    }
}
console.log(largest)

Output

180

In this JavaScript code finds the largest number in an array. It initializes the largest variable with the first element of the marks array. It then iterates through each element, updating largest whenever it finds a larger number. After looping through all the elements, it prints the largest number. For the array [99, 50, 180, 70], the output is 180.

Example to find smallest number from given array

const marks = [100, 50, 40, 180, 70, 181]
let smallest = marks[0]
for (const num of marks)
{
    if(num<smallest)
    {
        smallest=num
    }
}
console.log(smallest)

Output

40

In this JavaScript code finds the smallest number in an array. It initializes the smallest variable with the first element of the marks array. It then iterates through each element, updating smallest whenever it finds a larger number. After looping through all the elements, it prints the smallest number. For the array [99, 50, 40, 180, 70], the output is 40.

Example to find sum of odd number from given array

const numbers = [5, 8, 10, 20, 7, 13]
let sum = 0
for (let i=0; i<numbers.length; i++)
{
    if(numbers[i] % 2 == 1)
    {
        sum+=numbers[i]
    }
}
console.log(`sum: ${sum}`)

Output

25

In this javascript code it calculates the sum of all odd numbers in an array. It initializes sum to 0 and iterates over each element in the numbers array. If an element is odd (checked using numbers[i] % 2 == 1), it adds that element to sum. Finally, it prints the total sum of the odd numbers. For the array [5, 8, 10, 20, 7, 13], the output is sum: 25.

Example to find sum of odd and even number from given array

const numbers = [5, 8, 10, 20, 7, 13];
let sumOdd = 0;
let sumEven = 0;

for (let i = 0; i < numbers.length; i++) {
    if (numbers[i] % 2 == 1) {
        sumOdd += numbers[i];
    } else {
        sumEven += numbers[i];
    }
}

console.log(`Sum of odd numbers: ${sumOdd}`);
console.log(`Sum of even numbers: ${sumEven}`);

Output:

Sum of odd numbers: 25
Sum of even numbers: 38

In this JavaScript code it calculates the sum of odd and even numbers separately from an array. It initializes sumOdd and sumEven to 0 and iterates through each number in the numbers array. If a number is odd (numbers[i] % 2 == 1), it adds it to sumOdd; otherwise, it adds it to sumEven. Finally, it prints the sums of odd and even numbers. For the array [5, 8, 10, 20, 7, 13], it outputs Sum of odd numbers: 25 and Sum of even numbers: 38.

Implementing Queue using Array​

Implementing Queue using Array