C Programming Interview Questions Declarations and Initializations

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 & Explanation 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

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2.	What are the types of linkages?
	A. Internal and External B. External, Internal and None C. External and None D. Internal Answer & Explanation 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.

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3.	Which of the following special symbol allowed in a variable?
	A. * (asterisk) B. | (pipeline) C. - (hyphen) D. _ (underscore) Answer & Explanation 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

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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 & Explanation 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.

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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 & Explanation 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