Question - What is Regular expressions? 
          
        
        Answer - 
        
-Regular expressions is used to perform powerful and efficient text processing
-It is simple like search editors and powerful text processing language
-This is powerful pattern language
-Matching performed based on the bit pattern used for the encoding the character not based graphic representation of the character
-Regualr expressions composed with two types of characters 
1)meta characters (like *)  
2)litrals