How to check file extension using C++

[Mamo Grag]

Hello
I am trying to make a program that check any file and get the extension like :
*If i have image.png the program well return a that this file has a png extension etc...
So any one who help me with a source code.
Thank you C++ers

[AbstractionAnon]

https://en.cppreference.com/w/cpp/filesystem/path/extension

Requires C++17

[Duthomhas]

You don't really even need that. Just check to see if the last four characters in the filename == ".png".

[thmm]

The extension doesn't have to be 3 characters long. The OP wants to check any file type.

[lastchance]

#include <iostream>
#include <string>
using namespace std;

string getExtension( const string &str )
{
   size_t p = str.rfind( '.' );
   if ( p == string::npos || p == str.size() - 1 ) return "";
   return str.substr( p + 1 );
}

int main()
{
   string tests[] = { "one.doc", "two.xls", "help", "spam.txt.exe" };
   for ( string s : tests )
   {
      string ext = getExtension( s );
      cout << s << " : " << ( ext.empty() ? "No extension" : "extension " + ext ) << '\n';
   }
}

one.doc : extension doc
two.xls : extension xls
help : No extension
spam.txt.exe : extension exe

[Duthomhas]

"hello.world/filename"

http://www.cplusplus.com/forum/general/34348/#msg185786


[edit]
These days, though, you can just use filesystem::path, as AbstractionAnon suggested. He even linked to some good examples. :O)