INTERVIEW QUESTIONS IN C : 1

1.

Which of the following statements are correct about the below program? #include int main() { int i = 0; i++; if(i <= 5) { printf("IndiaBIX\n"); exit(); main(); } return 0; }

A. The program prints 'IndiaBIX' 5 times B. The program prints 'IndiaBIX' one time C. The call to main() after exit() doesn't materialize. D. The compiler reports an error since main() cannot call itself. Answer: Option B Explanation: Step 1: int i = 0; here variable i is declared as an integer type and initialized to '0'(zero). Step 2: i++; here variable i is increemented by 1(one). Hence, i = 1 Step 3: if(i <= 5) becomes if(1 <= 5) here we are checking '1' is less than or equal to '5'. Hence the if condition is satisfied. Step 4: printf("IndiaBIX\n"); It prints "IndiaBIX" Step 5: exit(); terminates the program execution. Hence the output is "IndiaBIX". Learn more problems on : Control Instructions Discuss about this problem : Discuss in Forum

2.

What will be the output of the program? #include int main() { float a=0.7; if(a < 0.7f) printf("C\n"); else printf("C++\n"); return 0; }

A. C B. C++ C. Compiler error D. Non of above Answer: Option B Explanation: if(a < 0.7f) here a is a float variable and 0.7f is a float constant. The float variable a is not less than 0.7f float constant. But both are equal. Hence the if condition is failed and it goes to else it prints 'C++' Example: #include int main() { float a=0.7; printf("%.10f %.10f\n",0.7f, a); return 0; } Output: 0.6999999881 0.6999999881 Learn more problems on : Floating Point Issues Discuss about this problem : Discuss in Forum

3.	Which of the following is suitable data type for the variable a in the statement given below? (datatype) a = 23.45;
	A. float B. double C. long double D. long float Answer: Option A Learn more problems on : Floating Point Issues Discuss about this problem : Discuss in Forum

4.	Functions cannot return more than one value at a time
	A. True B. False Answer: Option A Explanation: True, A function cannot return more than one value at a time. because after returning a value the control is given back to calling function. Learn more problems on : Functions Discuss about this problem : Discuss in Forum

5.	What will be the output of the program? #include #define JOIN(s1, s2) printf("%s=%s %s=%s \n", #s1, s1, #s2, s2); int main() { char *str1="India"; char *str2="BIX"; JOIN(str1, str2); return 0; }
	A. str1=IndiaBIX str2=BIX B. str1=India str2=BIX C. str1=India str2=IndiaBIX D. Error: in macro substitution Answer: Option B Learn more problems on : C Preprocessor Discuss about this problem : Discuss in Forum

6.	Macros with arguments are allowed
	A. True B. False Answer: Option A Explanation: True, A macro may have arguments. Example: #define CUBE(X)(X*X*X) Learn more problems on : C Preprocessor Discuss about this problem : Discuss in Forum

7.	If a variable is a pointer to a structure, then which of the following operator is used to access data members of the structure through the pointer variable?
	A. '.' B. '&' C. '*' D. '->' Answer: Option D Learn more problems on : Pointers Discuss about this problem : Discuss in Forum

8.	Point out the error in the program #include int main() { int *x; *x=100; return 0; }
	A. Error: invalid assignment for x B. Error: suspicious pointer conversion C. No error D. None of above Answer: Option C Explanation: While reading the code there is no error, but upon running the program having an unitialised variable can cause the program to crash (Null pointer assignment). Learn more problems on : Pointers Discuss about this problem : Discuss in Forum

9.	Are the expression *ptr++ and ++*ptr are same?
	A. True B. False Answer: Option B Explanation: *ptr++ increments the pointer and not the value, whereas the ++*ptr increments the value being pointed by ptr Learn more problems on : Pointers Discuss about this problem : Discuss in Forum

10.	What will be the output of the program ? #include int main() { static char mess[6][30] = {"Don't walk in front of me...", "I may not follow;", "Don't walk behind me...", "Just walk beside me...", "And be my friend." }; printf("%c, %c\n", *(mess[2]+9), *(*(mess+2)+9)); return 0; }
	A. t, t B. k, k C. n, k D. m, f Answer: Option B Learn more problems on : Strings Discuss about this problem : Discuss in Forum

11.	Union elements can be of different sizes.
	A. True B. False Answer: Option A Learn more problems on : Structures, Unions, Enums Discuss about this problem : Discuss in Forum

12.	Is it necessary that the size of all elements in a union should be same?
	A. Yes B. No Answer: Option B Learn more problems on : Structures, Unions, Enums Discuss about this problem : Discuss in Forum

13.	What is the purpose of "rb" in fopen() function used below in the code? FILE *fp; fp = fopen("source.txt", "rb");
	A. open "source.txt" in binary mode for reading B. open "source.txt" in binary mode for reading and writing C. Create a new file "source.txt" for reading and writing D. None of above Answer: Option A Explanation: The file source.txt will be opened in the binary mode. Learn more problems on : Input / Output Discuss about this problem : Discuss in Forum

14.	What will be the output of the program ? #include int main() { printf("%%%%\n"); return 0; }
	A. %%%%% B. %% C. No output D. Error Answer: Option B Learn more problems on : Input / Output Discuss about this problem : Discuss in Forum

15.	stderr, stdin, stdout are FILE pointers
	A. Yes B. No Answer: Option A Explanation: Yes, these will be declared like The corresponding stdio.h variable is FILE* stdin; The corresponding stdio.h variable is FILE* stdout; The corresponding stdio.h variable is FILE* stderr; Learn more problems on : Input / Output Discuss about this problem : Discuss in Forum

16.	What will be the output of the program (myprog.c) given below if it is executed from the command line? cmd> myprog 1 2 3 /* myprog.c */ #include #include int main(int argc, char **argv) { int i, j=0; for(i=0; i"%d\n", j); return 0; }
	A. 123 B. 6 C. Error D. "123" Answer: Option B Learn more problems on : Command Line Arguments Discuss about this problem : Discuss in Forum

17.	What will be the output of the program (myprog.c) given below if it is executed from the command line? cmd> myprog one two three /* myprog.c */ #include #include int main(int argc, char **argv) { int i; for(i=1; i<=3; i++) printf("%u\n", &argv[i]); return 0; } If the first value printed by the above program is 65517, what will be the rest of output?
	A. 65525 65531 B. 65519 65521 C. 65517 65517 D. 65521 65525 Answer: Option B Learn more problems on : Command Line Arguments Discuss about this problem : Discuss in Forum

18.	Bitwise | can be used to set multiple bits in number.
	A. Yes B. No Answer: Option A Learn more problems on : Bitwise Operators Discuss about this problem : Discuss in Forum

19.	What do the following declaration signify? int (*ptr)[30];
	A. ptr is a pointer to an array of 30 integer pointers. B. ptr is a array of 30 integer function pointer. C. ptr is a array of 30 integer pointers. D. ptr is a array 30 pointers. Answer: Option A Learn more problems on : Complicated Declarations Discuss about this problem : Discuss in Forum

20.	We can allocate a 2-Dimensional array dynamically.
	A. True B. False Answer: Option A Learn more problems on : Complicated Declarations Discuss about this problem : Discuss in Forum