➨ C Programming Declarations And Initialization

1. What is the output of the program given below ? #include int main() { enum status { pass, fail, atkt}; enum status stud1, stud2, stud3; stud1 = pass; stud2 = atkt; stud3 = fail; printf("%d, %d, %d\n", stud1, stud2, stud3); return 0; }

A. 0, 1, 2 B. 1, 2, 3 C. 0, 2, 1 D. 1, 3, 2 - Answer&Explanation Answer:Option C Explanation : enum takes the format like {0,1,2..) so pass=0, fail=1, atkt=2 stud1 = pass (value is 0) stud2 = atkt (value is 2) stud3 = fail (value is 1) Hence it prints 0, 2, 1 View Answer

2. What will be the output of the program in 16 bit platform (Turbo C under DOS)? #include int main() { extern int i; i = 20; printf("%d\n", sizeof(i)); return 0; }

A. 2 B. 4 C. vary from compiler D. Linker Error : Undefined symbol 'i' - Answer&Explanation Answer:Option D Explanation : Linker Error : Undefined symbol 'i' The statement extern int i specifies to the compiler that the memory for 'i' is allocated in some other program and that address will be given to the current program at the time of linking. But linker finds that no other variable of name 'i' is available in any other program with memory space allocated for it. Hence a linker error has occurred. View Answer

3. 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 #include 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 View Answer

4. What are the types of linkages?

A. Internal and External B. External and None C. External, Internal and None D. Internal - Answer&Explanation Answer:Option C 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. View Answer

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

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  View Answer

6. 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.

View Answer

7. 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 #include int main() { printf("\n Result : %f" , ceil(1.44) ); printf("\n Result : %f" , ceil(1.66) ); printf("\n Result : %f" , floor(1.44) ); printf("\n Result : %f" , floor(1.66) ); return 0; } // Output: // Result : 2.000000 // Result : 2.000000 // Result : 1.000000 // Result : 1.000000 View Answer

8. By default a real number is treated as a

A. float B. double C. long double D. far double - Answer&Explanation Answer:Option B Explanation : In computing, 'real number' often refers to non-complex floating-point numbers. It include both rational numbers, such as 42 and 3/4, and irrational numbers such as pi = 3.14159265... When the accuracy of the floating point number is insufficient, we can use the double to define the number. The double is same as float but with longer precision and takes double space (8 bytes) than float. To extend the precision further we can use long double which occupies 10 bytes of memory space. View Answer

9. Which of the following is not user defined data type? 1 : struct book { char name[10]; float price; int pages; }; 2 : long int l = 2.35; 3 : enum day {Sun, Mon, Tue, Wed};

A. 1 B. 2 C. 3 D. 1 & 2 - Answer&Explanation Answer:Option B Explanation : C data types classification are Primary data types int char float double void Secondary data types (or) User-defined data type Array Pointer Structure Union Enum So, clearly long int l = 2.35; is not User-defined data type. (i.e.long int l = 2.35; is the answer.) View Answer

10. Is the following statement a declaration or definition? extern int i;

A. Declaration B. Definition C. Error D. Function - Answer&Explanation Answer:Option A Explanation : Declaring is the way a programmer tells the compiler to expect a particular type, be it a variable, class/struct/union type, a function type (prototype) or a particular object instance. (ie. extern int i) Declaration never reserves any space for the variable or instance in the program's memory; it simply a "hint" to the compiler that a use of the variable or instance is expected in the program. This hinting is technically called "forward reference". View Answer

11. Identify which of the following are declarations 1 : extern int x; 2 : float square ( float x ) { ... } 3 : double pow(double, double);

A. 1 B. 2 C. 1 & 3 D. 3 - Answer&Explanation Answer:Option C Explanation : extern int x; - is an external variable declaration. double pow(double, double); - is a function prototype declaration. Therefore, 1 and 3 are declarations. 2 is definition. View Answer

12. In the following program where is the variable a getting defined and where it is getting declared? #include int main() { extern int a; printf("%d\n", a); return 0; } int a=20;

A. extern int a is declaration, int a = 20 is the definition B. int a = 20 is declaration, extern int a is the definition C. int a = 20 is definition, a is not defined D. a is declared, a is not defined - Answer&Explanation Answer:Option A Explanation : - During declaration we tell the datatype of the Variable. - During definition the value is initialized. View Answer

13. When we mention the prototype of a function?

A. Defining B. Declaring C. Prototyping D. Calling - Answer&Explanation Answer:Option B Explanation : A function prototype in C or C++ is a declaration of a function that omits the function body but does specify the function's name, argument types and return type. While a function definition specifies what a function does, a function prototype can be thought of as specifying its interface. View Answer

14. What is the output of the program? #include int main() { extern int a; printf("%d\n", a); return 0; } int a=20;

A. 20 B. 0 C. Garbage Value D. Error - Answer&Explanation Answer:Option A Explanation : extern int a; indicates that the variable a is defined elsewhere, usually in a separate source code module. printf("%d\n", a); it prints the value of local variable int a = 20. Because, whenever there is a conflict between local variable and global variable, local variable gets the highest priority. So it prints 20. View Answer

15. What is the output of the program in Turbo C (in DOS 16-bit OS)? #include int main() { char *s1; char far *s2; char huge *s3; printf("%d, %d, %d\n", sizeof(s1), sizeof(s2), sizeof(s3)); return 0; }

A. 2, 4, 6 B. 4, 4, 2 C. 2, 4, 4 D. 2, 2, 2 - Answer&Explanation Answer:Option C Explanation : Any pointer size is 2 bytes. (only 16-bit offset) So, char *s1 = 2 bytes. So, char far *s2; = 4 bytes. So, char huge *s3; = 4 bytes. A far, huge pointer has two parts: a 16-bit segment value and a 16-bit offset value. Since C is a compiler dependent language, it may give different output in other platforms. The above program works fine in Windows (TurboC), but error in Linux (GCC Compiler). View Answer

16. What is the output of the program? #include int main() { struct emp { char name[20]; int age; float sal; }; struct emp e = {"Tiger"}; printf("%d, %f\n", e.age, e.sal); return 0; }

A. 0, 0.000000 B. Garbage values C. Error D. None of these - Answer&Explanation Answer:Option A Explanation : When an automatic structure is partially initialized remaining elements are initialized to 0(zero). View Answer

17. What will be the output of the program? #include int X=40; int main() { int X=20; printf("%d\n", X); return 0; }

A. 20 B. 40 C. Error D. No Output - Answer&Explanation Answer:Option A Explanation : Whenever there is conflict between a local variable and global variable, the local variable gets priority. View Answer

18. What is the output of the program? #include int main() { int x = 10, y = 20, z = 5, i; i = x < y < z; printf("%d\n", i); return 0; }

A. 0 B. 1 C. Error D. None of these - Answer&Explanation Answer:Option B Explanation : Since x < y turns to be TRUE it is replaced by 1. Then 1 < z is compared and to be TRUE. The 1 is assigned to i. View Answer

19. What is the output of the program? #include int main() { extern int fun(float); int a; a = fun(3.14); printf("%d\n", a); return 0; } int fun(int aa) { return (int)++aa; }

A. 0 B. 3 C. 4 D. Compile Error - Answer&Explanation Answer:Option D Explanation : 2 Errors 1. Type mismatch in redeclaration of fun 2. Type mismatch in parameter aa View Answer

20. What is the output of the program? #include int main() { int a[5] = {2, 3}; printf("%d, %d, %d\n", a[2], a[3], a[4]); return 0; }

A. Garbage Values B. 2, 3, 3 C. 3, 2, 2 D. 0, 0, 0 - Answer&Explanation Answer:Option D Explanation : When an automatic array is partially initialized, the remaining elements are initialized to 0. View Answer

21. What is the output of the program? #include int main() { union a { int i; char ch[2]; }; union a u; u.ch[0] = 3; u.ch[1] = 2; printf("%d, %d, %d\n", u.ch[0], u.ch[1], u.i); return 0; }

A. 3, 2, 515 B. 515, 2, 3 C. 3, 2, 5 D. None of these - Answer&Explanation Answer:Option A Explanation : printf("%d, %d, %d\n", u.ch[0], u.ch[1], u.i); It prints the value ofu.ch[0] = 3, u.ch[1] = 2 and it prints the value of u.i means the value of entire union size. So the output is 3, 2, 515. View Answer

22. In the following program how long will the for loop get executed? #include int main() { int i=5; for(;scanf("%s", &i); printf("%d\n", i)); return 0; }

A. The for loop would not get executed at all B. The for loop would get executed only once C. The for loop would get executed 5 times D. The for loop would get executed infinite times - Answer&Explanation Answer:Option D Explanation : During the for loop execution scanf() ask input and then printf() prints that given input. This process will be continued repeatedly because, scanf() returns the number of input given, the condition is always true(user gives a input means it reurns '1'). Hence this for loop would get executed infinite times. View Answer

23. What will be the output of the program? #include int main() { int X=40; { int X=20; printf("%d ", X); } printf("%d\n", X); return 0; }

A. 40 40 B. 20 40 C. 20 D. Error - Answer&Explanation Answer:Option B Explanation : In case of a conflict between a local variable and global variable, the local variable gets priority. View Answer

24. Point out the error in the following program (if it is compiled with Turbo C compiler). #include int main() { display(); return 0; } void display() { printf("MCQBIX.com"); }

A. No Error B. display() doesn't get invoked C. display() is called before it is defined D. None of these - Answer&Explanation Answer:Option C Explanation : In this program the compiler will not know that the function display() exists. So, the compiler will generate "Type mismatch in redeclaration of function display()". To over come this error, we have to add function prototype of function display(). Another way to overcome this error is to define the function display() before the int main(); function. #include void display(); /* function prototype */ int main() { display(); return 0; } void display() { printf("MCQBIX"); } Output: MCQBIX Note: This problem will not occur in modern compilers (this problem occurs in TurboC but not in GCC). View Answer

25. Point out the error in the following program. #include int main() { void v = 0; printf("%d", v); return 0; }

A. Error: Declaration syntax error 'v' (or) Size of v is unknown or zero. B. Program terminates abnormally. C. No error D. None of these. - Answer&Explanation Answer:Option A Explanation : No answer description available for this question.  View Answer

26. Point out the error in the following program. #include struct emp { char name[20]; int age; }; int main() { emp int xx; int a; printf("%d\n", &a); return 0; }

A. Error: in printf B. Error: in emp int xx; C. No error D. None of these - Answer&Explanation Answer:Option B Explanation : There is an error in the line emp int xx; To overcome this error, remove the int and add the struct at the begining of emp int xx; #include struct emp { char name[20]; int age; }; int main() { struct emp xx; int a; printf("%d\n", &a); return 0; } View Answer

27. Which of the following is correct about err used in the declaration given below? typedef enum error { warning, test, exception } err;

A. It is a typedef for enum error. B. It is a variable of type enum error. C. The statement is erroneous. D. It is a structure. - Answer&Explanation Answer:Option A Explanation : A typedef gives a new name to an existing data type.  So err is a new name for enum error. View Answer

28. Point out the error in the following program. #include int main() { int (*p)() = fun; (*p)(); return 0; } int fun() { printf("IndiaBix.com\n"); return 0; }

A. Error: in int(*p)() = fun; B. Error: fun() prototype not defined C. No error D. None of these - Answer&Explanation Answer:Option B Explanation : The compiler will not know that the function int fun() exists. So we have to define the function prototype of int fun(); To overcome this error, see the below program #include int fun(); /* function prototype */ int main() { int (*p)() = fun; (*p)(); return 0; } int fun() { printf("IndiaBix.com\n"); return 0; } View Answer

29. Which of the declaration is correct?

A. int length; B. char int; C. int long; D. float double; - Answer&Explanation Answer:Option A Explanation : int length; denotes that variable length is int(integer) data type. char int; here int is a keyword cannot be used a variable name. int long; here long is a keyword cannot be used a variable name. float double; here double is a keyword cannot be used a variable name. So, the answer is int length; View Answer

30. Which of the following operations are INCORRECT?

A. int i = 35; i = i%5; B. short int j = 255; j = j; C. long int k = 365L; k = k; D. float a = 3.14; a = a%3; - Answer&Explanation Answer:Option D Explanation : float a = 3.14; a = a%3; gives "Illegal use of floating point" error. The modulus (%) operator can only be used on integer types. We have to use fmod()function in math.h for float values. View Answer

31. Which of the following correctly represents a long double constant?

A. 6.68 B. 6.68L C. 6.68f D. 6.68LF - Answer&Explanation Answer:Option B Explanation : 6.68 is double.  6.68L is long double constant.  6.68f is float constant.  6.68LF is not allowed in c.  View Answer

32. Which of the structure is incorrcet? 1 : struct aa { int a; float b; }; 2 : struct aa { int a; float b; struct aa var; }; 3 : struct aa { int a; float b; struct aa *var; };

A. 1 B. 2 C. 3 D. 1, 2, 3 - Answer&Explanation Answer:Option B Explanation : Option B gives "Undefined structure in 'aa'" error. View Answer

33. Which of the structure is correct? 1 : struct book { char name[10]; float price; int pages; }; 2 : struct aa { char name[10]; float price; int pages; } 3 : struct aa { char name[10]; float price; int pages; }

A. 1 B. 2 C. 3 D. All of these - Answer&Explanation Answer:Option A Explanation : In 2 and 3 semicolon are missing in structure element. View Answer

34. Which of the structure is correct? 1 : typedef long a; extern int a c; 2 : typedef long a; extern a int c; 3 : typedef long a; extern a c;

A. 1 correct B. 2 correct C. 3 correct D. 1, 2, 3 are correct - Answer&Explanation Answer:Option C Explanation : typedef long a; extern int a c; while compiling this statement becomes extern int long c;. This will result in to "Declaration syntax error". typedef long a; extern a int c; while compiling this statement becomes extern long int c;. This will result in to "Too many types in declaration error". typedef long a; extern a c; while compiling this statement becomes extern long c;. This is a valid c declaration statement. It says variable c is long data type and defined in some other file or module. View Answer