what are stack and queue? example of stack and queue. write a program of the stack for pop. make a queue using two stacks. what is schema? have you ever created a table? how many keys are there in SQL? what is a foreign key, primary key, candidate key? what will be the candidate key in the student table? give me the stud_id of that student who belongs to a given key. what is deadlock? given two strings check if they are anagrams or not. ex - str1: ABC str2: bac op: true ex - str1: ABC str 2: baac op: false