C Programming - Declarations and Initializations

1. 

Which of the declaration is correct?

A. int length;
B. char int;
C. int long;
D. float double;

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;(Option A).


2. 

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: 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.


3. 

Which of the following correctly represents a long double constant?

A. 6.68
B. 6.68L
C. 6.68f
D. 6.68LF

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.


4. 

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: Option B

Explanation:

Option B gives "Undefined structure in 'aa'" error.


5. 

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 above

Answer: Option A

Explanation:

In 2 and 3 semicolon are missing in structure element.