contents : strlen() strcmp() strcpy() strcat() strncpy() strncat() strncmp() strchr() strrchr() strstr()

1. Strings
String library functions
Nishma jagadish 1

2. String library functions
Strlen()
Strcmp()
Strcpy()
Strcat()
Strncpy()
Strncat()
Strncmp()
Strchr()
Strrchr()
Strstr()
Nishma jagadish 2

3. Strlen()
Size_t strlen (char const *string);
Eg:
main()
{
Int l;
Char str[20];
Str[]=“nishma”;
L=strlen (str);
Printf(“length = %d”,l);
}
o/p : length=6
Nishma jagadish 3

4. Strcmp()
int strcmp (const char *str1, const char *str2);
Eg:
main()
{
Int l;
Char str1[20] , str2[20];
Str1[]=“new”;
Str2[]=“new”;
L=strcmp (str1,str2);
Printf(“%d”,l);
}
o/p : 0
If s1<s2 o/p < 0
If s1==s2 o/p == 0
If s1>s2 o/p > 0
Nishma jagadish 4

5. Strcpy()
Char *strcpy (char *str1 , const char str2);
Eg:
main()
{
Char str1[20], str2[20];
Str1[]=“newyear”;
Str2[]=“York”;
strcpy (str1, str2);
Printf(“str1=%s, str2=%s”,str1,str2);
}
o/p :
Str1=“York”
Str2=“York”
Source
Dest
strcpy (str1, str2);
strcpy (str1, “York”);
strcpy (“new”, str2);
strcpy (“new”, “York”);
Nishma jagadish 5

6. Strcat()
char *strcat (char *str1, const char *str2);
Eg:
main()
{
Char str1[20] , str2[20];
Str1[]=“new”;
Str2[]=“york”;
strcat (str1,str2);
Printf(“str1=%s, str2=%s”,str1,str2);
}
o/p :
Str1=“newyork”
Str2=“York”
Nishma jagadish 6

7. Strncpy()
Char *strncpy (char *str1 , const char str2 , size_t n);
Eg:
main()
{
Int n=6;
Char str1[20], str2[20];
Str1[]=“department”;
Str2[]=household”;
strncpy (str1, str2,n);
Printf(“str1=%s, str2=%s”,str1,str2);
}
o/p :
Str1=“househment”
Str2=“household”
Source
Dest
strncpy (str1, str2,n);
strncpy (str1, “York”,n);
strncpy (“new”, str2,n);
strncpy (“new”, “York”,n);
Nishma jagadish 7

8. Strncat()
char *strncat (char *str1, const char *str2, size_t n);
Eg:
main()
{
Int n =6;
Char str1[20] , str2[20];
Str1[]=“department”;
Str2[]=“household”;
strncat (str1,str2,n);
Printf(“str1=%s, str2=%s”,str1,str2);
}
o/p :
Str1=“departmenthouseh”
Str2=“household”
Nishma jagadish 8

9. Strncmp()
int strncmp (const char *str1, const char *str2, size_t n);
Eg:
main()
{
Int l,n=4;
Char str1[20] , str2[20];
Str1[]=“newyear”;
Str2[]=“newyork”;
L=strncmp (str1,str2,n);
Printf(“%d”,l);
}
o/p :
If n=4, l==0
If n>4, and length of str1<str2, l is negative
If n>4, and length of str1<str2, l is positive
If s1<s2 o/p < 0
If s1==s2 o/p == 0
If s1>s2 o/p > 0
Nishma jagadish 9

10. Strchr()
char *strchr (const char *str , int ch);
Eg:
main()
{
Char str[20],*p;
Str[]=“department”;
P=strchr (str1, ‘e’);
Printf(“p=%s”,p);
}
o/p :
P = epartment
If the char is not present it returns null
First occurance(left most)
Nishma jagadish 10

11. Strrchr()
char *strrchr(const char *str , int ch);
Eg:
main()
{
Char str[20],*p;
Str[]=“department”;
P=strrchr (str, ‘e’);
Printf(“p=%s”,p);
}
o/p :
P = ent
If the char is not present it returns null
Last occurance(right most)
Nishma jagadish 11

12. Strstr()
char *strstr (const *s1 , const char *s2);
Eg:
main()
{
Char str1[20], str2[20];
Str1[]=“destination block”;
Str2[]=“nation”;
P=strstr (str1, str2);
Printf(“str1=%s , str2=%s”,str1,str2);
}
o/p :
Str1=nation block
Str2=nation
If str2 is station this string is not
present in str1 hence returns a
null
Used to locate the first
occurrence of a substring
in another string
Nishma jagadish 12

13. Thank you
Nishma jagadish 13