This document discusses strings and pointers in C programming. It explains that pointers can be used to manipulate strings and develop user-defined functions that perform the same tasks as standard string library functions like strlen(), strcpy(), and strcmp(). Examples are provided for user-defined versions of strlen(), strcpy(), strcmp(), and strcat() to illustrate how to use pointers to replicate the behavior of these common string functions.

1. Lecture 17Lecture 17
Version 1.0Version 1.0
Strings and PointersStrings and Pointers

2. 2Rushdi Shams, Dept of CSE, KUET, Bangladesh
Strings and PointersStrings and Pointers
 we have seen some of the string librarywe have seen some of the string library
functionsfunctions
 The best use of pointers to manipulate stringThe best use of pointers to manipulate string
can be illustrated with the help of making thosecan be illustrated with the help of making those
library functions into user defined functionslibrary functions into user defined functions
 means you can develop user defined functionsmeans you can develop user defined functions
that will perform exactly the same way strln ( ),that will perform exactly the same way strln ( ),
strcpy ( ), and strcmp ( ) worksstrcpy ( ), and strcmp ( ) works

3. 3Rushdi Shams, Dept of CSE, KUET, Bangladesh
User Defined strlen ( )User Defined strlen ( )

4. 4Rushdi Shams, Dept of CSE, KUET, Bangladesh
User defined strcpy ( )User defined strcpy ( )

5. 5Rushdi Shams, Dept of CSE, KUET, Bangladesh
User defined strcmp ( )User defined strcmp ( )

6. 6Rushdi Shams, Dept of CSE, KUET, Bangladesh
User defined strcat ( )User defined strcat ( )

7. 6Rushdi Shams, Dept of CSE, KUET, Bangladesh
User defined strcat ( )User defined strcat ( )