CS2112 ASSIGNMENT 1 Solution

1. Naming convention for your programs: cs21xx-assign1-progy.c (assuming cs21xx denotes your roll number and progy denotes the program number).
2. To submit the solution files (.c or .h), ensure that they not password protected and mail them together to <assignisik@gmail.com> with the subject line as follows:
5. Submissions from different students having significant match will be debarred from evaluation.
NOTE: Unless otherwise specified, all programs should take the required inputs from stdin, and print the desired outputs to stdout.
Q1. Let us define the DOMINATING FOLDING of a string of length n as the folding of a string from the middle such that the bigger (by ASCII value) of the characters at the indices i and (n−i) are retained. If the folding happens from the left or right, the bigger of ith and (n − i)th characters are retained at the end or beginning, respectively. Note that the DOMINATING FOLDING will turn the string into exactly half of its length except for the cases where the length of the string is odd. Write a program that takes a string and a series of folding instructions and returns the result.
[20 marks]
Input Format
The input (to be read from stdin) comprises the input string followed by a series of folding instructions represented either as ‘L’ or ‘R’, denoting DOMINATING FOLDING from the left or right, respectively.
Output Format
The output (to be printed to stdout) will show the intermediate and final strings after performing the DOMINATING FOLDING(s). The output strings are to be separated by space in the same line at which they are printed.
Sample Input 0
Computing LL
Sample Output 0
utmog mtu
Sample Input 1
123456 LRL
Sample Output 1
456 65 6
Sample Input 2
+-*/ LLLLL
Sample Output 2
-/ / / / /
Q2. Consider the traversal of elements in a two-dimensional integer matrix as shown in the following figure. Note that the traversal starts from the bottom-right corner and pursue the directions up-left-down-right recursively. Write a program that takes a two-dimensional matrix as user input and returns the elements traversed in the said way. Your should write a recursive function for the traversal.

[20 marks]
Input Format
The input (to be read from stdin) is a two-dimensional integer matrix. The first line of the input comprises the row and column numbers of the matrix. This will be followed by the entries of the matrix in row-major fashion.
Output Format
The output (to be printed to stdout) is the list of traversed elements.
Sample Input 0
2 2
1 2
3 4
Sample Output 0
4 2 1 3
Sample Input 1
3 3
1 2 3
4 5 6 7 8 9 Sample Output 1 9 6 3 2 1 4 7 8 5
Sample Input 2
4 4
1 2 3 4
5 6 7 8
9 10 11 12
13 14 15 16
Sample Output 2
16 12 8 4 3 2 1 5 9 13 14 15 11 7 6 10
Q3. Recall that an ASCII string is a string that comprises ASCII characters only. Write a program that takes an ASCII string as a command-line argument and expands the non-numeric characters that are preceded by a numeric character within it. An expansion of a character increases the occurrence of it by one. The preceding numeric character will denote the number of times it has to be expanded. Hence, not all the characters will necessarily get expanded. The numeric characters used for expanding the succeeding non-numeric characters disappear in the resulting string, while the rest of the numeric characters remain. [20 marks]
Input Format
The input (to be read as command-line argument) is an ASCII string.
Output Format
The output (to be printed to stdout) is the expanded string.
Sample Input 0 d2ata
Sample Output 0 daaata
Sample Input 1
245
Sample Output 1
245
Sample Input 2 tricky3.50c
Sample Output 2
tricky....5c