Regular Expressions 101

^start of line

\s*?any whitespace character, repeated any number of times

Group 1((?:virtual\s*|const\s*|friend\s*){0,3})

Non-Capturing Group(?:virtual\s*|const\s*|friend\s*){0,3}

{0,3}repeats the group contents below between 0 and 3 times:

1st Alternativevirtual\s*

virtualthe literal text virtual (case sensitive)

\s*any whitespace character, repeated any number of times

2nd Alternativeconst\s*

constthe literal text const (case sensitive)

\s*any whitespace character, repeated any number of times

3rd Alternativefriend\s*

friendthe literal text friend (case sensitive)

\s*any whitespace character, repeated any number of times

\s*any whitespace character, repeated any number of times

Group 2([\w]*?)

Character Class[\w]*?

*?matches any number of characters from the set below:

\wany word character

\s*any whitespace character, repeated any number of times

\w+any word character, repeated at least once

\s*any whitespace character, repeated any number of times

::the literal text ::

\s*any whitespace character, repeated any number of times

Group 3([\w]+)

Character Class[\w]+

+matches at least one character from the set below:

\wany word character

\s*any whitespace character, repeated any number of times

Group 4(\(.*\))

\(the literal ( (40₁₀ / 50₈ / 28₁₆)

.*any character (except for line terminators), repeated any number of times

\)the literal ) (41₁₀ / 51₈ / 29₁₆)

\s*any whitespace character, repeated any number of times

Group 5(const)?

?repeats the group contents below at most once:

constthe literal text const (case sensitive)

\s*any whitespace character, repeated any number of times

Character Class[{|:]

{the literal { (123₁₀ / 173₈ / 7B₁₆)

|the literal | (124₁₀ / 174₈ / 7C₁₆)

:the literal : (58₁₀ / 72₈ / 3A₁₆)

Global pattern flags

g modifier: global. Finds all matches instead of stopping after the first

m modifier: multiline. Causes ^ and $ to match the start and end of each line, not only the start and end of the string

Detailed match information will be displayed here automatically.

Search reference

Regular Expression

^\s*?((?:virtual\s*|const\s*|friend\s*){0,3})\s*([\w]*?)\s*\w+\s*::\s*([\w]+)\s*(\(.*\))\s*(const)?\s*[{|:]

Test String
New

#include <iostream>
#include <iomanip>
#include "Time.h"
using namespace std;

Time :: Time(const int h, const int m, const int s) 
  : hour(h), minute (m), second(s)
{}

virtual const void Time :: setTime(const int h, const int m, const int s) 
{
     hour = h;
     minute = m;
     second = s;     
}		
 
std::string Time :: print() const
{
     cout << setw(2) << setfill('0') << hour << ":"
	<< setw(2) << setfill('0') << minute << ":"
 	<< setw(2) << setfill('0') << second << "\n";	
 
}
 
bool Time :: equals(const Time &otherTime)
{
     if(hour == otherTime.hour 
          && minute == otherTime.minute 
          && second == otherTime.second)
          return true;
     else
          return false;
}

Extraction
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