HackerRank Building a Smart IDE: Identifying comments Solution

// my  program in C++

#include <iostream>
/** playing around in
a new programming language **/
using namespace std;

int main ()
{
  cout << "Hello World";
  cout << "I'm a C++ program"; //use cout
  return 0;
}

#include<iostream>
using namespace std;
int main()
{
	string line;
	bool multi=false;
	while(getline(cin,line))
	{
		bool printed=false;
		bool single=false;
		for(int i=0;i<line.length();i++)
		{
			if(line[i]=='/'&&line[i+1]=='/'&&!multi) single=true;
			else if(line[i]=='/'&&line[i+1]=='*') multi=true;
			if(single||multi) {cout<<line[i];printed=true;}
			if(line[i-1]=='\n'&&single) single=false;
			else if(line[i]=='/'&&line[i-1]=='*'&&multi) multi=false;
		}
		if(printed) cout<<endl;
		printed=false;
	}
}

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.io.StringReader;
import java.util.Arrays;

public class Solution {
	static BufferedReader br;
	static PrintWriter out;
	static String INPUT = "";
	
	static void solve() throws Exception
	{
		StringBuilder sb = new StringBuilder();
		while(true){
			String line = br.readLine();
			if(line == null)break;
			sb.append(line).append("\n");
		}
		char[] s = sb.toString().toCharArray();
		int n = s.length;
		boolean multiline = false;
		boolean singleline = false;
		int start = -1;
		for(int i = 0;i < s.length;i++){
			if(!multiline && !singleline && i+1 < n && s[i] == '/' && s[i+1] == '*'){
				multiline = true;
				start = i;
				i++;
			}else if(multiline && !singleline && i+1 < n && s[i] == '*' && s[i+1] == '/'){
				multiline = false;
				out.println(new String(s, start, (i+1)-start+1));
			}else if(!multiline && !singleline && i+1 < n && s[i] == '/' && s[i+1] == '/'){
				singleline = true;
				start = i;
				i++;
			}else if(singleline && s[i] == '\n'){
				singleline = false;
				out.println(new String(s, start, i-1-start+1));
			}
		}
	}
	
	public static void main(String[] args) throws Exception
	{
		long S = System.currentTimeMillis();
		br = new BufferedReader(INPUT.isEmpty() ? new InputStreamReader(System.in) : new StringReader(INPUT));
		out = new PrintWriter(System.out);
		
		solve();
		out.flush();
		long G = System.currentTimeMillis();
		tr(G-S+"ms");
	}
	
	static void tr(Object... o) { if(INPUT.length() != 0)System.out.println(Arrays.deepToString(o)); }
}

# Enter your code here. Read input from STDIN. Print output to STDOUT
import collections
import re

def get_input():
    import sys
    return sys.stdin.read()

TEXT = get_input()

Token = collections.namedtuple('Token', ['typ', 'value', 'line', 'column'])

def get_comments(s):
    # Tokenizing the text
    token_specification = [
        ('COMMENT_SINGLE_START',  r'//'),
        ('COMMENT_SINGLE_END', r"\n"),
        ('COMMENT_MULTI_START',  r'/\*'),
        ('COMMENT_MULTI_END',  r'\*/'),
        ('QUOTE', r'"')
    ]
    # Single regex match...
    tok_regex = '|'.join('(?P<%s>%s)' % pair for pair in token_specification)

    line = 1
    pos = line_start = 0
    in_single = in_multi = in_string = False
    single_start = None
    multi_start = None
    string_start = None

    for match in re.finditer(tok_regex, s):
        typ = match.lastgroup
        if not (in_multi or in_single) and typ == "QUOTE":
            in_string = not in_string
        elif not (in_multi or in_string) and not in_single and typ == "COMMENT_SINGLE_START":
            in_single = True
            single_start = match.start()
        elif not (in_multi or in_string) and in_single and typ == "COMMENT_SINGLE_END":
            in_single = False
            yield s[single_start:match.start()]
            single_start = None
        elif not (in_single or in_string) and not in_multi and typ == "COMMENT_MULTI_START":
            in_multi = True
            multi_start = match.start()
        elif not (in_single or in_string) and in_multi and typ == "COMMENT_MULTI_END":
            in_multi = False
            yield s[multi_start:match.end()]
            multi_start = None

for comment in get_comments(TEXT):
    print (comment)

function processData(input) {
    var m,i;
    m = input.match(/\/\/.*$|\/\*(?:.|\n)*?\*\//gm)
    if (m){
        for (i=0;i<m.length;i++){
            console.log(m[i]);
        }
    }
} 

process.stdin.resume();
process.stdin.setEncoding("ascii");
_input = "";
process.stdin.on("data", function (input) {
    _input += input;
});

process.stdin.on("end", function () {
   processData(_input);
});

<?php
$file = file_get_contents("php://stdin");
/* Enter your code here. Read input from STDIN. Print output to STDOUT */
preg_match_all('/\/\*[\s\S]*?\*\/|\/\/.*/',$file,$matches);
echo implode($matches[0],"\n");
?>