Variables And Datatypes (C Programming MCQs)

This section focuses on the “Variables And Datatypes” of the C programming. These Multiple Choice Questions (MCQs) should be practiced to improve the C programming skills required for various interviews (campus interview, walk-in interview, company interview), placement, entrance exam, and other competitive examinations.

1. How many keywords are there in c ?

A. 31
B. 32
C. 64
D. 63

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2. Which of the following is true for variable names in C?

A. Variable names cannot start with a digit
B. Variable can be of any length
C. They can contain alphanumeric characters as well as special characters
D. Reserved Word can be used as variable name

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3. Which of the following cannot be a variable name in C?

A. true
B. friend
C. export
D. volatile

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4. What is the output of this program?

        
void main()
{
int x = 10;
float x = 10;
printf("%d", x)
}

A. Compilations Error
B. 10
C. 10.0000
D. 10.10

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5. What is the output of this program?

    #include <stdio.h>
int main()
{
int i;
for (i = 0;i < 5; i++)
int a = i;
printf("%d", a);
}

A. Syntax error in declaration of a
B. No errors, program will show the output 5
C. Redeclaration of a in same scope throws error
D. a is out of scope when printf is called

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6. What is the output of this program?

  #include <stdio.h>
int var = 20;
int main()
{
int var = var;
printf("%d ", var);
return 0;
}

A. Garbage Value
B. 20
C. Compiler Error
D. None of these

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7. What is size of int in C ?

A. 2 bytes
B. 4 bytes
C. 8 bytes
D. Depends on the system/compiler

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8. Range of double is -1.7e-38 to 1.7e+38 (in 16 bit platform – Turbo C under DOS)

A. True
B. False

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9. Which is false?

A. Constant variables need not be defined as they are declared and can be defined later
B. Global constant variables are initialized to zero
C. const keyword is used to define constant values
D. You cannot reassign a value to a constant variable

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10. Array is ______ datatype in C Programming language.

A. Derived Data type
B. Primitive Data type
C. Custom Data type
D. None of these

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11. If you pass an array as an argument to a function, what actually gets passed?

A. Address of last element of Array
B. Value of first element
C. Base address of array
D. Value of elements in array

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12. When double is converted to float, the value is?

A. Rounded
B. Truncated
C. Depends on the standard
D. Depends on the compiler

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13. Which of the following is not a logical operator?

A. !
B. &&
C. ||
D. |

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14. Which of the following can have different meaning in different contexts?

A. &
B. *
C. Both A and B
D. None of the above

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15. Which of the following is not a valid declaration in C?
    1. short int x;
    2. signed short x;
    3. short x;
    4. unsigned short x;

A. 1 and 2
B. 2 and 4
C. 3 and 4
D. All are valid

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16.The minimum number of temporary variable needed to swap the content two variables is?

A. 2
B. 3
C. 0
D. 1

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17.What is short int in C programming?

A. The basic data type of C
B. Qualifier
C. Short is the qualifier and int is the basic datatype
D. All of the mentioned

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18. The precedence of arithmetic operators is (from highest to lowest)?

A. %, *, /, +, –
B. %, +, /, *, –
C. %, +, -, *, /
D. +, -, %, *, /

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19. Which of the following data type will throw an error on modulus operation(%)?

A. int
B. char
C. float
D. long

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20.Relational operators cannot be used on:

A. String
B. float
C. long
D. structure

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21. What is the output of this program?

          
int main()
{
char ch;
ch = 128;
printf("%d\n", ch);
return 0;
}

A. 128
B. -128
C. Depends on compiler
D. None of the above

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22. What is the output of this program?

int main()
{
float x = 'a';
printf("%f", x);
return 0;
}

A. a
B. a.000000
C. 97.000000
D. Run time error

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23. How would you round off a value from 6.66 to 7.0?

A. ceil(6.66)
B. floor(6.66)
C. roundup(6.66)
D. roundto(6.66)

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24. What will be the output of the program in 16 bit platform ?

#include<stdio.h>
int main()
{
extern int i;
i = 20;
printf("%d\n", sizeof(i));
return 0;
}

A. 2
B. 4
C. 8
D. Linker Error

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25. What will be output when you will execute following c code?

#include<stdio.h>
int main()
{
printf("%d\t",sizeof(5.5));
printf("%d\t",sizeof(50000));
printf("%d",sizeof('A'));
return 0;
}

A. 4 2 1
B. 8 4 4
C. 8 4 2
D. compiler dependent

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26. What is the output of this program?

void main()
{
int i=0, j=1, k=2, m;
m = i++ || j++ || k++;
printf("%d %d %d %d", m, i, j, k);
}

A. 1 1 2 3
B. 1 1 2 2
C. 0 1 2 2
D. 0 1 2 3

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27. What is the output of this program?

        
void main()
{
int c = - -14;
printf("%d", c);
}

A. 13
B. 14
C. -14
D. Compilation Error

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28. What is the output of this program?

void main()
{
int i=5;
i = !i>10;
printf("%d", i);
}

A. 5
B. 10
C. 0
D. None of the above

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29. What is the output of this program?

		 
void main()
{
int p, q, r, s;
p = 1;
q = 2;
r = p, q;
s = (p, q);
printf("p=%d q=%d", p, q);
}

A. p=1 q=1
B. p=1 q=2
C. p=2 q=2
D. Invalid Syntex

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30. What is the output of this program?

void main()
{
printf("%x",-1<<4);
}

A. fff0
B. fff1
C. fff2
D. fff3

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31. What is the output of this program?

#include<stdio.h>
void main()
{
int a=1, b=2, c=3, d;
d = (a=c, b+=a, c=a+b+c);
printf("%d %d %d %d", d, a, b, c);
}

A. 11 3 5 11
B. 11 1 5 11
C. 11 3 2 11
D. 11 3 3 11

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32. What is the output of this program?

void main()
{
int a, b = 5, c;
a = 5 * (b++);
c = 5 * (++b);
printf("%d %d",a,c);
}

A. 30 35
B. 30 30
C. 25 30
D. 25 35

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33. What is the output of this program?

#include<stdio.h>
int main(){
printf("%d",EOF);
return 0;
}

A. 0
B. 1
C. -1
D. NULL

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34. What is the output of this program?

#include<stdio.h>
int main(){
char num = '\010';
printf("%d", num);
return 0;
}

A. 010

B. 08

C. 10

D. 8

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35. What is the output of this program?

#include<stdio.h>
int main(){
void num=10;
printf("%v", num);
return 0;
}

A. Compilation error

B. 10

C. Garbage value

D. 0

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36. What is the output of this program?

#include<stdio.h>
int main(){
printf("%d\t",sizeof(2.5));
printf("%d\t",sizeof(2));
printf("%d",sizeof('A'));
return 0;
}

A. 8 4 2

B. 8 4 1

C. 4 4 1

D. 2.5 2 A

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37. What is the output of this program?

#include<stdio.h>
int main(){
signed a;
unsigned b;
a = 6u + -16 + 16u + -6;
b = a + 1;
if(a == b)
printf("%d %d",a,b);
else
printf("%u %u",a, b);
return 0;
}

A. Compilation error

B. 0 0

C. 0 1

D. address address

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38. By default a real number is treated as a

A. float
B. double
C. long double
D. far double

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39. The format identifier ‘%i’ is also used for _____ data type?

A. char
B. int
C. float
D. double

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40. Variable names beginning with underscore is not encouraged. Why?

A. It is not standardized
B. To avoid conflicts since assemblers and loaders use such names
C. To avoid conflicts since library routines use such names
D. To avoid conflicts with environment variables of an operating system

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