C Programming - Library Functions

Answer: Option D

Explanation:

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);

Answer: Option D

Explanation:

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.

Answer: Option A

Explanation:

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.

Answer: Option C

Explanation:

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).

Answer: Option D

Explanation:

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