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Objective Type Set
Online MCQ Assignment
Question Solution
Solved Question

1. Which is valid C expression?
a) int my_num = 100,000;
b) int my_num = 100000;
c) int my num = 1000;
d) int $my_num = 10000;

View Answer

Answer: b [Reason:] Space, comma and $ cannot be used in a variable name.

2. What is the output of this C code?

  1.     #include <stdio.h>
  2.     int main()
  3.     {
  4.         printf("Hello World! %d n", x);
  5.         return 0;
  6.     }

a) Hello World! x;
b) Hello World! followed by a junk value
c) Compile time error
d) Hello World!

View Answer

Answer: c [Reason:] It results in an error since x is used without declaring the variable x. Output: $ cc pgm1.c pgm1.c: In function ‘main’: pgm1.c:4: error: ‘x’ undeclared (first use in this function) pgm1.c:4: error: (Each undeclared identifier is reported only once pgm1.c:4: error: for each function it appears in.)

3. What is the output of this C code?

  1.     #include <stdio.h>
  2.     int main()
  3.     {
  4.         int y = 10000;
  5.         int y = 34;
  6.         printf("Hello World! %dn", y);
  7.         return 0;
  8.     }

a) Compile time error
b) Hello World! 34
c) Hello World! 1000
d) Hello World! followed by a junk value

View Answer

Answer: a [Reason:] Since y is already defined, redefining it results in an error. Output: $ cc pgm2.c pgm2.c: In function ‘main’: pgm2.c:5: error: redefinition of ‘y’ pgm2.c:4: note: previous definition of ‘y’ was here

4. Which of the following is not a valid variable name declaration?
a) float PI = 3.14;
b) double PI = 3.14;
c) int PI = 3.14;
d) #define PI 3.14

View Answer

Answer: d [Reason:] #define PI 3.14 is a macro preprocessor, it is a textual substitution.

5. What will happen if the below program is executed?

  1.     #include <stdio.h>
  2.     int main()
  3.     {
  4.         int main = 3;
  5.         printf("%d", main);
  6.         return 0;
  7.     }

a) It will cause a compile-time error
b) It will cause a run-time error
c) It will run without any error and prints 3
d) It will experience infinite looping

View Answer

Answer: c [Reason:] A C program can have same function name and same variable name. $ cc pgm3.c $ a.out 3

6. What is the problem in following variable declaration?
float 3Bedroom-Hall-Kitchen?;
a) The variable name begins with an integer
b) The special character ‘-‘
c) The special character ‘?’
d) All of the mentioned

View Answer

Answer: d [Reason:] A variable name cannot start with an integer, along with that the C compiler interprets the ‘-‘ and ‘?’ as a minus operator and a question mark operator respectively.

7. Comment on the output of this C code?

  1.     #include <stdio.h>
  2.     int main()
  3.     {
  4.         int ThisIsVariableName = 12;
  5.         int ThisIsVariablename = 14;
  6.         printf("%d", ThisIsVariablename);
  7.         return 0;
  8.     }

a) The program will print 12
b) The program will print 14
c) The program will have a runtime error
d) The program will cause a compile-time error due to redeclaration

View Answer

Answer: b [Reason:] Variable names ThisIsVariablename and ThisIsVariableName are both distinct as C is case sensitive. Output: $ cc pgm4.c $ a.out 14

8. Which of the following cannot be a variable name in C?
a) volatile
b) true
c) friend
d) export

View Answer

Answer: a [Reason:] volatile is C keyword.