Easy example of strstr(),strspn(),strrchr(),strchr(),strbrk(),memcpy(),memset(),memcmp() - #include

I have written quick example of few function such as strspn(),strrchr(),strchr(),strbrk(),memcpy() etc of C language.These function we often use for dealing with string. These code are very easy to read and write. I am just pasting the code here, Please read the comments and if you have any questions , please post comment!

strstr():

/*
 * use and example of strstr() function
 */
/*
 * The  strstr()  function finds the first occurrence of the substring needle in the string haystack. 
 * The terminating null bytes ('\0') are
 * not compared.
 */

#include 
#include 
int main(){
    char *str="what the hell! system got hacked!!!";
    char *str2="what";
    char *str3="system";
    printf("\n%s\n\n",strstr(str,str3));
    printf("%s\n\n",strstr(str,str2));
    return 0;
}

/* gcc strstr1.c -o strstr1
 * ./strstr1
 * system got hacked!!!
 * 
 * what the hell! system got hacked!!!
 * 
 */

strspn():

/* The use and example of strspn() */
/*search a string for a set of bytes. The strspn() 
 * function calculates the length (in bytes) of the initial segment of s which consists entirely of bytes in accept. */

#include 
#include 

int main(){
    char *str="C is a greate system language 1337";
    char *str2="1234567890";
    printf("Lets see %s\n",strspn(str,str2));
    return 0;
    
}

strrchr():

/*use and example of strrchr()*/
/*
 * The strrchr() function returns a pointer to the last occurrence of the character c in the string s.
 * This will search the char from last. For example if we search 'a' then it will point you "ammer"
 * from the "programmer"
 
 */

#include 
#include 

int main(){
    char *str="You are the programmer";
    int str1;
    printf("Enter a char:");
    scanf("%c",&str1);
    //int search=strrchr(str,str1);
    printf("\'%c\' found in \'%s\'\n",str1,strrchr(str,str1));
    return 0;
}

/*
 * pusheax@programming:~/codes/linux1blog$ gcc strrchar.c -o strrchar
 * pusheax@programming:~/codes/linux1blog$ ./strrchar
 * Enter a char:a
'a' found in 'ammer'
pusheax@programming:~/codes/linux1blog$ ./strrchar
Enter a char:u
'u' found in 'u are the programmer'
pusheax@programming:~/codes/linux1blog$ ./strrchar
Enter a char:o
'o' found in 'ogrammer'
pusheax@programming:~/codes/linux1blog$ ./strrchar
Enter a char:y
'y' found in '(null)'
pusheax@programming:~/codes/linux1blog$ ./strrchar
Enter a char:Y
'Y' found in 'You are the programmer'
pusheax@programming:~/codes/linux1blog$ 
*/

strchr():

/* The use and example of strchr() */

#include 
#include  /*include string.h for all the string related function*/    

int main(){
    char *strng="Mr. Stupid!"; //We will search the char in this string
    char secstr='S';        //Char should be closed in single quote
    int search=(strchr(strng,secstr) != NULL);  //The strchr() is the search function
    
    if (!search)                    //Compare if search variable is not true
        printf("The char is not found!\n");
    else                        //Otherwise it is true
        printf("Wow the char \'%c\' found in strng \"%s\"\n",secstr,strng);
    
    return 0;
}

strbrk():

/* use and example of strpbrk() */
/* strpbrk - search a string for any of a set of bytes */

#include 
#include 

int main(){
    char *str="Programming is another best way to learn hacking";
    char *str2="b";
    int search=*strpbrk(str,str2); //Is "b" in str2 in str?
    if (!search)
        printf("Nothing!\n");
    else 
        printf("Found \'%c\' in \"%s\"\n",search,str); //Yes it is, well print that what char it is. strpbrk is pointer to the char!
    return 0;
}

memcpy():

/*Use and example memcpy() and memmove()*/

/*memcpy - copy memory area*/

//memcpy() does not check the boundary. Be careful!

#include 
#include 


int main(){
    char str[10];
    char str1[]="Hello all hackers!";       
    memcpy(str,str1,sizeof(str1));          
    printf("%s\n",str);
    return 0;
}

memset():

//Use and example of memset()
//memset - fill memory with a constant byte

#include 
#include 

int main(){
    char str[]="Life is boring!";
    int str1='A';
    printf("First string:%s\n",str);
    printf("Now it is:%s\n",memset(str,str1,sizeof(str1)));
    return 0;
}

memcmp():

#include 
#include 

int main(){
    char str[]="ABa";
    char str1[]="AbA";
    int what=memcmp(str,str1,sizeof(str));
    if(what)
        printf("Return:%d not matched\n",what);
    else
        printf("Return:%d mean equal\n",what);
    
    printf("Lets print something different!\n");
    printf("Confused for:%d ?\n",memcmp(str,str1,2));
    printf("Another confusion for :%d ?\n",memcmp(str,str1,1));
    return 0;
}