▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓
▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒
▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓
▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓
String.h
--string.h is the header in the C standard library for the C programming language which contains macro definitions, constants, and declarations of functions and types used not only for string handling but also various memory handling functions; the name is thus something of a misnomer.
String copy functions
•strcpy() - copies a string to another
•strncpy() - copies n characters from a string to another
SAMPLE PROGRAM #1 [strcpy()]
#include <string.h>
#include <stdio.h>
#include <conio.h>
int main()
{
char s1[100],s2[100];
strcpy(s1,"hello");
printf(“%s”,s1);
getch();
}
SAMPLE PROGRAM #2 [strncpy()]
#include <string.h>
#include <stdio.h>
#include <conio.h>
int main()
{
char s1[100],s2[100];
strncpy(s1,"hello“,2);
printf(“%s”,s1);
getch();
}
String concatenation
•strcat() - concatenates two strings
•strncat() - concatenates n characters from a string onto another
SAMPLE PROGRAM #3 [strcat()]
#include <stdio.h>
#include <string.h>
int main ()
{
char str[80];
strcpy (str,"these ");
strcat (str,"strings ");
strcat (str,"are ");
strcat (str,"concatenated.");
puts (str); //printf in string.h
getch();
}
String Compare
•strcmp() - compares two strings
•strncmp() - compares n characters of two strings
SAMPLE PROGRAM #4 [strcmp()]
#include <stdio.h>
#include <string.h>
int main()
{
char s[10] = "testing", t[10];
strcpy(t, s);
if (strcmp(s, t)==0)
printf("The strings are identical.\n"); else
printf("The strings are different.\n");
getch();
}
Other String Functions
•strchr() - returns the first occurrence of character in a string
•strrchr() - returns the last occurrence of character in a string
•strspn() - returns the length of leading characters in a string that are contained in a specified string
•strcspn() - returns the length of leading characters in a string not contained in a specified string
SAMPLE PROGRAM #5 [strchr()]
#include <stdio.h>
#include <string.h>
int main ()
{
char str[] = "This is a sample string";
char * pch;
printf ("Looking for the 's' character in \"%s\"...\n“,str);
pch=strchr(str,'s');
while (pch!=NULL)
{
printf ("found at %d\n",pch-str+1);
pch=strchr(pch+1,'s');
}
getch();
}
[OUTPUT]
Looking for the 's' character in "This is a sample string"...
found at 4
found at 7
found at 11
found at 18
SAMPLE PROGRAM #6 [strrchr()]
#include <stdio.h>
#include <string.h>
int main ()
{
char str[] = "This is a sample string";
char * pch;
pch=strrchr(str,'s');
printf ("Last occurence of 's' found at %d \n",pch-str+1);
return 0;
}
[OUTPUT]
Last occurrence of 's' found at 18
CONTINUATION
•strpbrk () - returns first occurrence in a string of any character in another string
•strstr () - returns the first occurrence of one string in another
•strlen() - returns length of a string
•strtok() - returns a token from a string delimited by specified characters
•strrev() – reverses all characters except the null terminator.
SAMPLE PROGRAM #7 [strpbrk()]
#include <stdio.h>
#include <string.h>
int main ()
{
char str[] = "This is a sample string";
char key[] = "aeiou";
char * pch;
printf ("Vowels in '%s': ",str);
pch = strpbrk (str, key);
while (pch != NULL)
{
printf ("%c " , *pch);
pch = strpbrk (pch+1,key);
}
printf ("\n");
return 0;
}
[OUTPUT]
Vowels in 'This is a sample string': i i a a e i
SAMPLE PROGRAM #8 [strstr ()]
#include <stdio.h>
#include <string.h>
int main ()
{
char str[] ="This is a simple string";
char * pch;
pch = strstr (str,"simple");
strncpy (pch,"sample",6);
puts (str);
return 0;
}
[OUTPUT]
This is a sample string
SAMPLE PROGRAM #9 [strlen()]
#include <stdio.h>
#include <string.h>
int main ()
{
char szInput[256];
printf ("Enter a sentence: ");
gets (szInput);
printf ("The sentence entered is %u characters long.\n",strlen(szInput));
return 0;
}
[OUTPUT]
Enter sentence: just testing
The sentence entered is 12 characters long.
SAMPLE PROGRAM #10 [strtok()]
#include <stdio.h>
#include <string.h>
int main ()
{
char str[] ="- This, a sample string.";
char * pch;
printf ("Splitting string \"%s\" into tokens:\n",str);
pch = strtok (str," ,.-");
while (pch != NULL)
{
printf ("%s\n",pch);
pch = strtok (NULL, " ,.-");
}
return 0;
}
[OUTPUT]
Splitting string "- This, a sample string." into tokens:
This
a
sample
string
SAMPLE PROGRAM #11 [strtok()]
#include <stdio.h>
#include <string.h>
int main ()
{
char str[] =“reverse";
strrev(str);
puts(str);
return 0;
}
[OUTPUT]
esrever
▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓
▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒
▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓
▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒▓▒
