C# Programming Questions and Answers

1

Storage location used by computer memory to store data for usage by an application is ?

a

Pointers

b

Constant

c

Variables

d

None of the mentioned

correct answer c

‘Variables’ are essential locations in memory of computer that are reserved for storing data used by an application. Each variable is given a name by programmer and hence assigned a value .The name assigned to variable then used in C# code to access value assigned to variable.

2

Are the given codes :

1. Myclass class;

Myclass class2 = null;

2. int i;

int j = 0;

a

True for (1);False for (2)

b

True for (2);False for (1)

c

Both (1) and (2) are equivalents

d

Both (1) and (2) are not equivalents

correct answer c

When we create a type in ‘C#’, It automatically gets filled with padded zeroes. For the case of class (reference types) this equates to a null pointer. Hence, for code 1) Both variable values are equivalent to each other.Similarly, for code 2) i.e for value type (including int/float/double etc.), the type is passed with zeroes.Hence, they are equivalent.

3

What will be output of the following code?

staticvoid Main(string[] args)

{

char a ='A';

string b ="a";

Console.WriteLine(Convert.ToInt32(a));

Console.WriteLine(Convert.ToInt32(Convert.Tochar(b)));

Console.ReadLine()

}

a

1, 97

b

55, 97

c

65, 97

d

97, 1

correct answer c

ASCII value of character ‘a’ is 65 and ASCII value of string “a” is 97.
Output: 65,97

4

Select output for the following set of code:

staticvoid Main(string[] args)

{

constint a =5;

const int b = 6;

for(int i =1; i <=5; i++)

{

a = a * i;

b = b * i;

}

Console.WriteLine(a);

Console.WriteLine(b);

Console.ReadLine();

}

a

600, 720

b

Compile time error

c

25, 30

d

5, 6

correct answer b

The left hand side of an assignment must be a variable,property or indexer i.e for both ‘a’ and ‘b’

5

Select output for the following set of code:

staticvoid Main(string[] args)

{

string Name ="He is playing in a ground.";

char[] characters = Name.ToCharArray();

StringBuilder sb =new StringBuilder();

for(int i = Name.Length-1; i >=0;--i)

{

sb.Append(characters[i]);

}

Console.Write(sb.ToString());

Console.ReadLine();

}

a

He is playing in a grou

b

.ground a in playing is He

c

.dnuorg a ni gniyalp si eH

d

He playing a

correct answer c

Reversal of array of strings character by character.
Output: .dnuorg a ni gniyalp si eH

6

Difference between keywords 'var' and 'dynamic' is:

a

‘Var’ is introduced in C# (3.0) and ‘Dynamic’ is introduced in C# (4.0)

b

‘Var’ is a type of variable where declaration is done at compile time by compiler while ‘Dynamic’ declaration is achieved at runtime by compiler

c

For ‘Var’ Error is caught at compile time and for ‘Dynamic’ Error is caught at runtime

d

For ‘Var’ datatype the code as : var obj1 = 1; and var obj1=”I am a string” will also compile safely.For ‘Dynamic’ datatype the code as: dynamic obj1 =1; and dynamic obj1 = “I am a string” will create an error

correct answer a,b,c

Answer: Option (A), (B) and (C)

7

Select output of the given set of Code :

staticvoid Main(string[] args)

{

String name ="Dr.Gupta";

Console.WriteLine("Good Morning"+ name);

}

a

Dr.Gupta

b