SYSTEM SOFTWARE AND COMPILER DESIGN LABORATORY
No. of Lecture Hrs./ Week
Total No. of Lecture Hrs.
PART - A
LEX AND YACC PROGRAMS:
Execute the following programs using LEX:
1) a. Program to count the number of characters, words, spaces and lines in a given input file.
b.Program to count the numbers of comment lines in a given C program. Also eliminate them and copy the resulting program into separate file.
2) a. Program to recognize a valid arithmetic expression and to recognize the identifiers and operators present. Print them separately.
b. Program to recognize whether a given sentence is simple or compound.
3) Program to recognize and count the number of identifiers in a given input file.
Execute the following programs using YACC:
4) a. Program to recognize a valid arithmetic expression that uses operators +, -, * and /.
b. Program to recognize a valid variable, which starts with a letter, followed by any number of letters or digits.
5) a. Program to evaluate an arithmetic expression involving operators +, -, * and /.
b. Program to recognize strings ‘aaab’, ‘abbb’, ‘ab’ and ‘a’ using the grammar (anbn, n>= 0).
6) Program to recognize the grammar (anb, n>= 10).
PART - B
1. a) Non-recursive shell script that accepts any number of argument and prints them in the Reverse order, (For example, if the script is named rargs, then executing rargs A B C should produce C B A on the standard output).
b) C program that creates a child process to read commands from the standard input and execute them (a minimal implementation of a shell – like program). You can assume that no arguments will be passed to the commands to be executed
2. a) Shell script that accepts two file names as arguments, checks if the permissions for these files are identical and if the permissions are identical, outputs the common permissions, otherwise outputs each file name followed by its permissions
b) C program to create a file with 16 bytes of arbitrary data from the beginning and another 16 bytes of arbitrary data from an offset of 48. Display the file contents to demonstrate how the hole in file is handled.
3. a) Shell function that takes a valid directory names as an argument and recursively descends all the subdirectories, finds the maximum length of any file in that hierarchy and writes this maximum value to the standard output
b) C program that accepts valid file names as command line arguments and for each of the arguments, prints the type of the file (Regular file, Directory file, Character special file, Block special file, Symbolic link etc.)
4. a) Shell script that accepts file names specified as arguments and creates a shell script that contains this file as well as the code to recreate these files. Thus if the script generated by your script is executed, it would recreate the original files(This is same as the “bundle” script described by Brain W. Kernighan and Rob Pike in “ The Unix Programming Environment”, Prentice – Hall India).
b) C program to do the following: Using fork( ) create a child process. The child process prints its own process-id and id of its parent and then exits. The parent process waits for its child to finish (by executing the wait( )) and prints its own process-id and the id of its child process and then exits.
1. Write a C program to implement the syntax-directed definition of “if E then S1” and “if E then S1 else S2”. (Refer Fig. 8.23 in the text book prescribed for 06CS62 Compiler Design, Alfred V Aho, Ravi Sethi, Jeffrey D Ullman: Compilers- Principles, Techniques and Tools, Addison-Wesley, 2007.)
2. Write a yacc program that accepts a regular expression as input and produce its parse tree as output.
In the examination, a combination of one LEX and one YACC problem has to be asked from part A for a total of 25 marks and one programming exercise from Part B has to be asked for a total of 25 marks.