What is oops in dart ?

First Technical round: Question asked based on data structure,networking,databases,coding,API,OOps concept,logical reasoning etc. 1.What is array? write a program to sort given array in ascending order(he told me to use editor but don't compile and run the program.After that he asked me which sorting algorithm you used here). 2.What is String? Write a program to check given string is palindrome or not. 3.What is object? 4.What is meant by inheritance? explain types. 5.If there are two classes one is parent and second is child. Child is class is extending parent class. Parent class consist of variable name "abc" ,if I use same variable name in child class and assign value "def". What will happen? 6.What is http protocol. Explain TCP and UDP. 7.What is DNS? 8.What is server? how it works? 9.Logical reasoning: If you have 5ltr & 3ltr measuring cups and you have to measure 4ltr water. How will you measure 4ltr water using that two cups? 10.If there is a wall having height 30 feet. A snail climbs 3feet each hr and sleeps down 2feet then how many hrs it will take to react till top of the wall. 11.What is API? 12.He gave a code in PHP: $a='1'; $b=&a; $c = 2&b; echo $a","$b; what will be the output? 13.Write a SQL query to display odd rows from emp table using unique key. 14.write a query to display unique mobile nos of employees from employee table. Task(duration 2 days): Given a API and asked to create a app and integrate it with that API which will display data in table view, give a search box ,follow and unfollow button functionality. Technical round with director: 1.Asked about projects which are mentioned in resume. 2.What is linked list?If I want to remove a middle node from linked list tell me the process to do this. 3.Write a program for a star pattern(triangle shape). 4.Write a program for factorials. 5.Without writing any code tell me which line you will modify the code to print factorial of alternative no.(means if factorial program gives output 5*4*3*2*1,then if we want to modify it like this 5*3*1 ) 6.aksed about databases which you have worked in past. 7.What is session storage?explain 8.Where will we used it? 9.How can you autheticate a user on login page? 10.If user put slash and page name in url instead of login page.it tries to go directly on next page how can we restrict them from going directly to next page without authentication. 11.What is API? 12.If there is ecommerce website in that I clicked in Add cart button. Explain the whole process what will happened in backend after clicking that button till the product get added into the cart. 13.If I have used local storage for this add cart button. I opened this website in laptop I added a product in cart and after that I closed my browser window and I login to that website in mobile then my cart will show that product. so if I have stored that product in browser storage of laptop then how it is showing that product in my mobile. 13.What is bootstrap? 14.What are the things we used to make a page responsive? 15.What is media query?