rewind() takes the file pointer to the beginning of the file. so that the next I/O operation will take place at the beginning of the file.
Example: rewind(FilePointer);

strrchr() returns a pointer to the last occurrence of character in a string.

Example:

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

int main()
{
    char str[30] = "12345678910111213";
    printf("The last position of '2' is %d.\n",
            strrchr(str, '2') - str);
    return 0;
}

Output: The last position of '2' is 14.

stdio.h, which stands for "standard input/output header", is the header in the C standard library that contains macro definitions, constants, and declarations of functions and types used for various standard input and output operations.

Do like this fprintf(stdout, "%s %d %f", str, i, a);

The standard error(stderr) stream is the default destination for error messages and other diagnostic warnings. Like stdout, it is usually also directed to the output device of the standard console (generally, the screen).

"fflush()" flush any buffered output associated with filename, which is either a file opened for writing or a shell command for redirecting output to a pipe or coprocess.
Example:
fflush(FilePointer);
fflush(NULL); flushes all streams.

The randomize() function initializes the random number generator with a random value based on time. You can try the sample program given below in Turbo-C, it may not work as expected in other compilers.

/* Prints a random number in the range 0 to 99 */

#include <stdlib.h>
#include <stdio.h>
#include <time.h>

int main(void)
{
    randomize();
    printf("Random number in the 0-99 range: %d\n", random (100));
    return 0;
}

1. itoa() converts an integer to a string.
2. ltoa() converts a long to a string.
3. ultoa() converts an unsigned long to a string.
4. sprintf() sends formatted output to a string, so it can be used to convert any type of values to string type.

#include<stdio.h>
#include<stdlib.h>

int main(void)
{
   int   num1 = 12345;
   float num2 = 5.12;
   char str1[20];
   char str2[20];

   itoa(num1, str1, 10); /* 10 radix value */
   printf("integer = %d string = %s \n", num1, str1);

   sprintf(str2, "%f", num2);
   printf("float = %f string = %s", num2, str2);

   return 0;
}

// Output:
// integer = 12345 string = 12345
// float = 5.120000 string = 5.120000

memcmp compares the first 2 bytes of the blocks dest and src as unsigned chars. So, the ASCII value of 97 is 'a'.

if((i = memcmp(dest, src, 2))==0) When comparing the array dest and src as unsigned chars, the first 2 bytes are same in both variables.so memcmp returns '0'.
Then, the if(0=0) condition is satisfied. Hence the output is "Got it".

scanf() returns the number of variables to which you are provding the input. i = scanf("%d %d", &i, &i); Here Scanf() returns 2. So i = 2.

printf("%d\n", i); Here it prints 2.