To design an online simulator that checks whether a given input string (program snippet) is a single/multi-comment or not a comment.
Given a string, representing a program snippet, the task is to check if the given string is a single/multi-line comment or not a comment.
Types of Comment:
Single Line Comment:
Comments preceded by a Double Slash (‘//’)
Multi-line Comment:
Comments starting with (‘/*’) and ending with (‘*/’).
Check if at the first Index(i.e. index 0) the value is ‘/’ then follow below steps else print “It is not a comment”.
If line[0] == ‘/’:
o If line[1] == ‘/’, then print “It is a single line comment”.
o If line[1] == ‘*’, then traverse the string and if any adjacent pair of ‘*’ & ‘/’ is found then print “It is a multi-line comment”.
Otherwise, print “It is not a comment”.
Input: line = “/* Comment */”
Output: It is a multi-line comment
Input: line = “// Comment ”
Output: It is a single-line comment
Click on this Link to go to the Online Simulator.
We wrote the online simulator using C programming language and integrated it with the website designed using HTML, CSS, JavaScript. The simulator takes a string as input and checks whether it is a single/multi-line comment or not a comment.
There can be two possible sources of error for this string in the program snippet:
Unterminated Multi-Line Comments:
It occurs when we do not terminate the comment with a valid set of characters (here the red-coloured */). Single line comment does not need to terminate, and it starts by a double slash (//), but, multi-line comment needs to be terminated by */ (asterisk and slash). If a multi-line comment is not terminated properly, then during lexical analysis phase of the compiler, the compiler will consider everything after start of the multi-line comment as a comment and ignore them during tokenization (traversing the program from left to right line-by-line and breaking them down into tokens or logical units of a program).
Nested Multi-Line Comments:
In C, multi-line comments, /* and */, do not nest ie, if we want to write a nested comment (comment within comment), the compiler during lexical analysis phase will consider the first /* as start of multi-line comment and ignore the second /* syntax as it has still not got an end for the first comment “*/”. So, the multi-line comment will end after the first */ (red coloured). After that, the rest of the comment will not be ignored and will be considered during tokenization until it again gets a start of comment line again.