Write c-programs to solve the following problems. Each program should be written in a
separate .c file, which should compile using any C11 compliant compiler. Upload a zipfile
containing all the programs at the submissions portal



1. (25 marks) Large integers like 31415926535897932384626433832795028841971693993751
can be represented by a linked list of its digits (with the least significant digit at the
beginning of the list).
(a) Write a function that reads a positive integer as a character string of decimal
digits, and returns a linked list storing the number in the format mentioned above.
(b) Write a function to add two large integers in the above format.
(c) Write a function to multiply two large integers in the above format.
(d) Write a main function which calls the above developed functions to allow users to
add and multiply large integers and display the output.


2. (25 marks) A file input.txt stores student records. The first line of the file stores the
count n of students. This is followed by n lines, each storing a roll number (a string
like 19CS60Z99), the CGPA of the student (a real number like 8.76), and finally the
name of the student (may contain spaces). The three fields in each line are
separated by one or more spaces (or tabs).
Write a program to read the student records, sort the records based on student
names, and write the sorted records to a file output.txt in the format Name RollNo
CGPA. You may use any sorting algorithm.


3. (25 marks) You are given a list of dates as an array of strings. Write a program to
sort the dates chronologically, and print the sorted list. You can use any sorting
algorithm.
(a) The dates are provided in the EU format DD-MMM-YYYY, like 17-Jul-2019.
(b) The dates are provided in the US format MMM DD, YYYY, like Jul 17, 2019.



4. (25 marks) Let n > k > 0 be integers. Write a recursive function to print all the kelement subsets of {1,2, 3, ..., n}. Write the main function which calls the above
function after taking n and k as input from the user. It should also print the total
number of such subsets that it has printed by counting the number of prints (Do not
calculate using a formula)