Note: An operation with only one operand is called unary operation. Unary operators: ! Logical NOT operator. ~ bitwise NOT operator. sizeof Size-of operator. && Logical AND is a logical operator. Therefore, 1, 2, 3 are unary operators.

Note: 2. Arithmetic operators: *, /, %, +, - 1. Relational operators: >, <, >=, <=, ==, != 3. Logical operators : !, &&, || 4. Assignment operators: =

Note: The code won't compile since declaration of t cannot occur within parenthesis.

Note: The preprocessor replaces the line #include <stdio.h> with the system header file of that name. More precisely, the entire text of the file 'stdio.h' replaces the #include directive.

Note: char *strnset(char *s, int ch, size_t n); Sets the first n characters of s to ch

#include <stdio.h>
#include <string.h>

int main(void)
{
   char *string = "abcdefghijklmnopqrstuvwxyz";
   char letter = 'x';

   printf("string before strnset: %s\n", string);
   strnset(string, letter, 13);
   printf("string after  strnset: %s\n", string);

   return 0;
}

Output: string before strnset: abcdefghijklmnopqrstuvwxyz string after strnset: xxxxxxxxxxxxxnopqrstuvwxyz

Note: Declaration: strcmp(const char *s1, const char*s2); The strcmp return an int value that is if s1 < s2 returns a value < 0 if s1 == s2 returns 0 if s1 > s2 returns a value > 0

Note: The statement printf("\\n"); prints '\n' on the screen.

Note: he function strstr() Finds the first occurrence of a substring in another stringDeclaration: char *strstr(const char *s1, const char *s2);Return Value: On success, strstr returns a pointer to the element in s1 where s2 begins (points to s2 in s1). On error (if s2 does not occur in s1), strstr returns null.Example:

#include <stdio.h>
#include <string.h>

int main(void)
{
   char *str1 = "VCampus", *str2 = "mp", *ptr;

   ptr = strstr(str1, str2);
   printf("The substring is: %s\n", ptr);
   return 0;
}

Output: The substring is: mpus

Note: gets(); collects a string of characters terminated by a new line from the standard input stream stdin

#include <stdio.h>

int main(void)
{
   char string[80];

   printf("Enter a string:");
   gets(string);
   printf("The string input was: %s\n", string);
   return 0;
}

Output: Enter a string: IndiaBIX The string input was: IndiaBIX

int xstrlen(char *s)
{
    int length=0;
    while(*s!='\0')
    {    length++; s++; }
    return (length);
}

int xstrlen(char s)
{
    int length=0;
    while(*s!='\0')
        length++; s++;
    return (length);
}

int xstrlen(char *s)
{
    int length=0;
    while(*s!='\0')
        length++;
    return (length);
}

int xstrlen(char *s)
{
    int length=0;
    while(*s!='\0')
        s++;
    return (length);
}

Note: Option A is the correct function to find the length of given string.Example:

#include<stdio.h>

int xstrlen(char *s)
{
    int length=0;
    while(*s!='\0')
    { length++; s++; }
    return (length);
}

int main()
{
    char d[] = "VCampus";
    printf("Length = %d\n", xstrlen(d));
    return 0;
}