C# Programming Questions and Answers

1

Which statement is correct about following c#.NET code ?

int[] a= {11, 3, 5, 9, 6};

a

’a’ is a reference to the array created on stack

b

’a’ is a reference to an object created on stack

c

’a’ is a reference to an object of a class that compiler drives from ‘System.Array’ class

d

None of the mentioned

correct answer c

A perfect way of defining single array in C# which is derived automatically from class ‘System.Array’

2

Which statement is correct about following set of code ?
int[, ]a={{5, 4, 3},{9, 2, 6}};

a

’a’ represents 1-D array of 5 integers

b

a.GetUpperBound(0) gives 9

c

’a’ represents rectangular array of 2 columns and 3 arrays

d

a.GetUpperBound(1) gives 2

correct answer c,d

By definition Options (C) and (D)

3

What is the advantage of using 2D jagged array over 2D rectangular array?

a

Easy initialization of elements

b

Allows unlimited elements as well as rows which had ‘0’ or are empty in nature

c

All of the mentioned

d

None of the mentioned

correct answer b

In many applications where 2 dimensional arrays are used,not all rows need to have all the elements i.e they are sparse.Many rows have 0 elements.In such cases it is better to use 2D jagged arrays as they allow unequal number of elements in each row and also allow for empty rows.

4

What is the output of the following set of code ?

staticvoid Main(string[] args)

{

int i, j;

int[, ] arr =newint[3, 3];

for(i =0; i <3;++i)

{

for(j =0; j <3;++j)

{

arr[i, j]= i *2+ i *2;

Console.WriteLine(arr[i, j]);

}

Console.ReadLine();

}

a

0,0,0 4,4,4 8,8,8

b

4,4,4 8,8,8 12,12,12

c

8,8,8 12,12,12 16,16,16

d

0,0,0 1,1,1, 2,2,2

correct answer a

Since,with each value of of ‘i’ the value of ‘j’ is executed three times i.e
for i = 0, j = 0, 0, 0, i = 1, j = 2, 2, 2.
Output: 0, 0, 0 4, 4, 4 8, 8, 8.

5

What is the output for the following set of code ?

staticvoid Main(string[] args)

{

double a =345.09;

byte c =(byte) a;

Console.WriteLine(c);

Console.ReadLine();

}

a

98

b

89

c

88

d

84

correct answer b

Type casting a larger variable into a smaller variable results in modules of larger variable by range of smaller variable. a is ‘345.09’ which is larger than byte’s range i:e -128 to 127.
Output : 89.

6

Which is the correct way of defining and initializing an array of 3 integers?

a

int[] a={78, 9, 54};

b

int[] a;
a = new int[3];
a[1] = 78;
a[2] = 9;
a[3] = 54;

c

int[] a;
a = new int{78, 9, 54};

d

int[] a;
a = new int[3]{78, 9, 54};

correct answer a,d

Answer: Option (A) and Option (D)

7

What is the output for the following set of code?

staticvoid Main(string[] args)

{

char A ='K';

char B = Convert.ToChar(76);

A++;

B++;

Console.WriteLine(A+" "+B);

Console.ReadLine();

}

a

M L

b

U L

c

L M

d

A B

correct answer c

“++” increments the value of character by 1. A and B are given values K and 76, when we use increment operator their values increments by 1, A and B becomes L and M.
Output: L, M.

8

Choose selective differences between an array in c# and array in other programming languages.

a

Declaring array in C# the square bracket([]) comes after the type but not after identifier

b

It is not necessary to declare size of an array with its type

c

No difference between declaration of array in c# as well as as in other programming languages

d

All of the above mentioned

correct answer a,b

1. When declaring an array in C#, the square brackets ([]) come after the type, not the identifier.Brackets after the identifier is
not legal syntax in C#.
example : int[] IntegerArray;
2. The size of the array is not part of its type as it is in the C language. This allows to declare an array and assign any array
of int objects to it, regardless of the array’s length.
int[] IntegerArray;
IntegerArray = new int[10];
IntegerArray = new int[50];