Datatypes in C

Datatypes:

‘C’ supports several different types of data.

The basic data types are listed below.

1. Fundamantal Data types:

int float char

2. Derived Data types:

Functions arrays pointers Structures unions

3. User defined Data types:

enum typedef

User defined data types:

Enum:

enum identifier{value1,value2,value3,…,value n } ;

We can declare variables as follows.

Enum identifier v1 , v2 , v3 , … , vn ;

E.g. : enum day { mon , tue , wed , … , sun } ;

enum day week_st , week_end ;

week_st = mon ;

week_end = fri ;

• The compiler automatically assigns integer digits beginning with ‘0’ to all enumeration constants.
• Automatic assignments can be overridden by assigning values to the enumeration constants.
• E.g. : enum day { mon , tue , wed = 5, … , sun };
• Here mon is assigned 0 and tue 1 and wed 5.
• The next constants following wed will have the values starting from 5+1.
• The definition and declaration can be combined in one statement.
• E.g. : enum day { mon , tue , wed , … , sun } week_st,week_end ;

Typedef:

Type definition allows users to define an identifier that would represent an existing data type.

The user defined data type identifier can later be used to declare variables.

typedef existing_datatype identifier

E.g. : typedef int unit ;

typedef float marks;

unit batch1 , batch2 ;

Marks m1 , m2 ;

1) There is a new data-type which can take as values natural numbers between (and including) 0 and 25. How many minimum bits are required to store this data-type. [Amcat]

Op 1: 4

Op 2: 5

Op 3: 1

Op 4: 3

Correct Op : 2

2) A data type is stored as an 6 bit signed integer. Which of the following cannot be represented by this data type? [Amcat]

Op 1: -12

Op 2: 0

Op 3: 32

Op 4: 18

Correct Op : 3

3) A language has 28 different letters in total. Each word in the language is composed of maximum 7 letters. You want to create a data-type to store a word of this language. You decide to store the word as an array of letters. How many bits will you assign to the data-type to be able to store all kinds of words of the language. [Amcat]

Op 1: 7

Op 2: 35

Op 3: 28

Op 4: 196

Correct Op : 2

4) A 10-bit unsigned integer has the following range: [Amcat]

Op 1: 0 to 1000

Op 2: 0 to 1024

Op 3: 1 to 1025

Op 4: 0 to 1023

Correct Op : 4

5) Rajni wants to create a data-type for the number of books in her book case. Her shelf can accommodate a maximum of 75 books. She allocates 7 bits to the data-type. Later another shelf is added to her book-case. She realizes that she can still use the same data-type for storing the number of books in her book-case. What is the maximum possible capacity of her new added shelf? [Amcat]

Op 1: 52

Op 2: 127

Op 3: 53

Op 4: 75

Correct Op : 1

6) A new language has 15 possible letters, 8 different kinds of punctuation marks and a blank character. Rahul wants to create two data types, first one which could store the letters of the language and a second one which could store any character in the language. The number of bits required to store these two data-types will respectively be:[Amcat]

Op 1: 3 and 4

Op 2: 4 and 3

Op 3: 4 and 5

Op 4: 3 and 5

Correct Op : 3

7)Parul takes as input two numbers: a and b. a and b can take integer values between 0 and 255. She stores a, b and c as 1-byte data type. She writes the following code statement to process a and b and put the result in c. [Amcat]

c = a + 2*b

To her surprise her program gives the right output with some input values of a and b, while gives an erroneous answer for others. For which of the following inputs will it give a wrong answer?

Op 1: a = 10 b = 200

Op 2: a = 200 b = 10

Op 3: a = 50 b = 100

Op 4: a = 100 b = 50

Correct Op : 1

8)Prashant takes as input 2 integer numbers, a and b, whose value can be between 0 and 127. He stores them as 7 bit numbers. He writes the following code to process these numbers to produce a third number c.

c = a - b

In how many minimum bits should Prashant store c? [Amcat]

Op 1: 6 bits

Op 2: 7 bits

Op 3: 8 bits

Op 4: 9 bits

Correct Op : 3

9) Ankita takes as input 2 integer numbers, a and b, whose value can be between 0 and 31. He stores them as 5 bit numbers. He writes the following code to process these numbers to produce a third number c.

c = 2*(a - b)

In how many minimum bits should Ankita store c? [Amcat]

Op 1: 6 bits

Op 2: 7 bits

Op 3: 8 bits

Op 4: 9 bits

Correct Op : 2

10) A character in new programming language is stored in 2 bytes. A string is represented as an array of characters. A word is stored as a string. Each byte in the memory has an address. The word "Mahatma Gandhi" is stored in the memory with starting address 456. The letter 'd' will be at which memory address? [Amcat]

Op 1: 468

Op 2: 480

Op 3: 478

Op 4: 467

Correct Op : 3

11) Stuti is making a questionnaire of True-false questions. She wants to define a data-type which stores the response of the candidate for the question. What is the most-suited data type for this purpose? [Amcat]

Op 1: integer

Op 2: boolean

Op 3: float

Op 4: character

Correct Op : 2

12) By default a real number is treated as a

Op 1. float

Op 2. double

Op 3. long double

Op 4. far double

Correct: Op 2

13) Which of the following is not a valid variable name declaration?

Op 1. int _a3;

Op 2. int a_3;

Op 3. int 3_a;

Op 4. int _3a

Correct: Op 3

14) Which of the following special symbol allowed in a variable name?

Op 1. * (asterisk)

Op 2. | (pipeline)

Op 3. - (hyphen)

Op 4. _ (underscore)

Correct: Op :4

15) In the following program where is the variable a getting defined and where it is getting declared?

#include<stdio.h>

int main()

{

extern int a;

printf("%d\n", a);

return 0;

}

int a=20;

Op 1. extern int a is declaration, int a = 20 is the definition

Op 2. int a = 20 is declaration, extern int a is the definition

Op 3. int a = 20 is definition, a is not defined

Op 4. a is declared, a is not defined

Correct: Op 1

16) Which of the following is a User-defined data type?

Op 1. typedef int Boolean;

Op 2. typedef enum {Mon, Tue, Wed, Thu, Fri} Workdays;

Op 3. struct {char name[10], int age};

Op 4. all of the mentioned

Correct: Op 4

17) What will be output of the following program?

#include<stdio.h>

int main()

{

int x;

x=10,20,30;

printf("%d",x);

return 0;

}

Op 1. 10

Op 2. 20

Op 3. 30

Op 4. 0

Op 5. Compilation error

Correct : Op 1

18) What will be output of the following c program?

#include<stdio.h>

int main()

{

int _=5;

int __=10;

int ___; ___=_+__;

printf("%i",___);

return 0;

}

Op1. 5

Op2. 10

Op3. 15

Op4. Compilation error

Op5. None of these

Correct: Op 3

Explanation: Variable name can have only underscore.

19) What will be output of the following program?

#include<stdio.h>

int main()

{

float a=0.7;

if(a<0.7)

{

printf("C");

}

Else

{

printf("C++");

}

return 0; }

Op1. C

Op2. C++

Op3. NULL

Op4. Compilation error

Op5.None of these

Correct: Op1