you will learn how to implement string functions in c and the alternative way to write a program without using functions

1. IMPLEMENTATION OF
STRING FUNCTIONS

2. Hello!
I Am Fazila Sadia
Roll No. : BM -014

3. What Are
Strings

4. “Strings are actually array of
characters terminated by a null
character.Each character occupies one
byte of memory.

5. String Functions
The prototypes of string functions
can be found in string.h file.The
following is a list of functions found
within the <string.h> header file:

6. strlen( )
name_variable=strlen(string_name);
Function strlen( ) returns value of type integer
Synatax Of strlen( ) :

7. Example

8. Without Using Built In Function

9. String Concatenation
String concatenation is the operation of
joining character strings end-to-end. For
example, the concatenation of "snow" and
"ball" is "snowball. For two sets of strings S1
and S2, the concatenation S1S2 consists of
all strings of the form vw where v is a string
from S1 and w is a string from S2 .

13. strcpy( )
Syntax Of strcpy
strcpy(dest,source);
Here, source and destination are
both the name of the string. This
statement, copies the content of
string source to the content of
string destination.

14. Example

16. If destination string length is less than source string, entire
source string value won’t be copied into destination string.
For example, consider destination string length is 20 and
source string length is 30.
If you want to copy 25 characters from source string using
strncpy( ) function, only 20 characters from source string
will be copied into destination string and remaining 5
characters won’t be copied and will be truncated.
strncpy( )
strncpy(dest,source,size of)
Syntax Of strcpy( ):

18. Syntax Of strcmp( )
int strcmp (str_1,str_2);
strcmp is case sensitive, i.e "a" and "A" are
treated as different characters

21. strncmp( )
Syntax Of strncmp( )
int strncmp(dest,source,size_t);
The strncmp function returns a negative, zero, or
positive integer depending on whether the first n
characters of the object pointed to by s1 are less
than, equal to, or greater than the first n characters of
the object pointed to by s2.
The strncmp function will stop comparing if a null
character is encountered in either s1 or s2

23. strcmpi( )
Syntax Of strcmpi
This function is not case i.e "a" and "A"
are considered same characters.The
strncmpi function returns a negative value
if string1<string2, zero if both are equal, or
positive integer if string1 > string2 .
int strcmpi(dest,source,size_t);

25. strlwr( )
Syntax : strlwr(string_name);

27. strupr( )

29. strrev( )
Syntax : strrev(string_name);

30. Thanks!
Any questions?