Interview-Collection/RemoveComment.h at master · bluepp/Interview-Collection · GitHub

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/*
  bluepp
  2014-12-22
  May the force be with me!

(F tel  )
Write a program to remove the C comments(/* */) and C++
comments(//) from a file.
The file should be declared in command line.
*/

/* http://geeksquiz.com/remove-comments-given-cc-program/ */

string removeComments(string prgm)
{
    int n = prgm.length();
    string res;

    // Flags to indicate that single line and multpile line comments
    // have started or not.
    bool s_cmt = false;
    bool m_cmt = false;


    // Traverse the given program
    for (int i=0; i<n; i++)
    {
        // If single line comment flag is on, then check for end of it
        if (s_cmt == true && prgm[i] == '\n')
            s_cmt = false;

        // If multiple line comment is on, then check for end of it
        else if  (m_cmt == true && prgm[i] == '*' && prgm[i+1] == '/')
            m_cmt = false,  i++;

        // If this character is in a comment, ignore it
        else if (s_cmt || m_cmt)
            continue;

        // Check for beginning of comments and set the approproate flags
        else if (prgm[i] == '/' && prgm[i+1] == '/')
            s_cmt = true, i++;
        else if (prgm[i] == '/' && prgm[i+1] == '*')
            m_cmt = true,  i++;

        // If current character is a non-comment character, append it to res
        else  res += prgm[i];
    }
    return res;
}