Declarations and Initializations

General Questions

1. Which of the following statements should be used to obtain a remainder after dividing 3.14 by 2.1 ?

A.            rem = 3.14 % 2.1;

B.            rem = modf(3.14, 2.1);

C.            rem = fmod(3.14, 2.1);

D.            Remainder cannot be obtain in floating point division.

Answer: Option C

Explanation:

fmod(x,y) - Calculates x modulo y, the remainder of x/y. 
This function is the same as the modulus operator. But fmod() performs floating point divisions.

Example:

#include <stdio.h>

#include <math.h>

int main ()

{

  printf ("fmod of 3.14/2.1 is %lf\n", fmod (3.14,2.1) );

  return 0;

}

Output:
fmod of 3.14/2.1 is 1.040000

2. What are the types of linkages?

A.            Internal and External      B.            External, Internal and None

C.            External and None          D.            Internal

Answer: Option B

Explanation:

External Linkage-> means global, non-static variables and functions.
Internal Linkage-> means static variables and functions with file scope.
None Linkage-> means Local variables.

3. Which of the following special symbol allowed in a variable?

A.            * (asterisk)         B.            | (pipeline)

C.            - (hyphen)          D.            _ (underscore)

Answer: Option D

Explanation:

Variable names in C are made up of letters (upper and lower case) and digits. The underscore character ("_") is also permitted. Names must not begin with a digit.

Examples of valid (but not very descriptive) C variable names:
=> foo 
=> Bar 
=> BAZ 
=> foo_bar 
=> _foo42 
=> _ 
=> QuUx 

4. Is there any difference between following declarations?

1 :        extern int fun();

2 :        int fun();

A.         Both are identical

B.         No difference, except extern int fun(); is probably in another file

C.         int fun(); is overrided with extern int fun();

D.         None of these

Answer: Option B

Explanation:

extern int fun(); declaration in C is to indicate the existence of a global function and it is defined externally to the current module or in another file.

int fun(); declaration in C is to indicate the existence of a function inside the current module or in the same file.

5. How would you round off a value from 1.66 to 2.0?

A.         ceil(1.66)         B.         floor(1.66)

C.         roundup(1.66) D.         roundto(1.66)

Answer: Option A

Explanation:

/* Example for ceil() and floor() functions: */

#include<stdio.h>

#include<math.h>

int main()

{

    printf("\n Result : %f" , ceil(1.66) );

    printf("\n Result : %f" , floor(1.66) );

    return 0;

}

// Output: Result : 2.000000

// Output: Result : 1.000000