Hi Vishnu,
Try to search in Google with string "SAP + ABAP Concept + PDF".
You will get numbers of book with basic concept. But if I suggest, after read any of the concept you try to implement the same from your ends and after implement, think yourself how you can reuse your own written code to get the same kind of output.
Writing the Number of Line code is not the concept, how best way you are providing the output and what is the processing time is taking by system is.
Regards.
Praveer.