int length; ifstream is; is.open ("text.txt", ios::binary ); is.seekg (0, ios::end); length = is.tellg(); int pos = 4; // example : lire a partir de 4 int taille = 10; // lire 10 chars char * buffer = new char[taille]; if((pos+taille) < length) { is.seekg (pos, ios::beg); is.read(buffer, taille); } is.close();