C# Questions & Answers on Basic Operation on Strings for Freshers

1. Which of the following string() method are used to compare two strings with each other?

a) CopyTo()
b) Copy()
c) Compare()
d) CompareTo()

Answer: b

Explanation: Creates a new string by copying one string to another.

2. Choose the base class for string() method :

a) System.Array
b) System.char
c) System.String
d) None of the mentioned

Answer: c

Explanation: String is an alias for the predefined “System.string” class from which most of the string() methods are derived.

3. What is output for the following set of code:

1.  static void Main(string[] args)

2.  {

3.      string s1 = " Cshr ";

4.      string s2 = s1.Insert(3 , " a ");

5.      string s3 = s2.Insert(5 , " p ");

6.      for (int i = 0;i < s3.Length; i++)

7.      Console.WriteLine(s3[i]);

8.      Console.ReadLine();

9.  }

a) Cshar
b) CsharP
c) Csharp
d) Cshrap

Answer: c

Explanation: Insertion of character ‘a’ at postion ‘3’ using insert() which returns a new string with a substring inserted at a specified location.
Output: Csharp

4. Which of the following statement is correct about a string in C#.NET?

a) The System.Array class is used to represent a string
b) A string has a zero-based index
c) A number cannot be represented in the form of a string
d) A string is mutable because it can be modified once it has been created

Answer: b

5. What is output for the following set of code?

1.  static void Main(string[] args)

2.  {

3.      string s1 = "Hello";

4.      string s2 = "hello";

5.      if (s1 == s2)

6.      Console.WriteLine("Equal");

7.      else

8.      Console.WriteLine("Unequal");

9.      if (s1.Equals (s2))

10.      Console.WriteLine("Equal");

11.      else

12.      Console.WriteLine("Unequal");

13.      Console.ReadLine();

14.  }

a) Equal
Unequal
b) Unequal
Equal
c) Equal
Equal
d) Unequal
Unequal

Answer: d

Explanation: In first comparison it is being checked either two strings are equal or not but in second comparison it is checked whether two references are equal or not.
Output: Unequal
Unequal

6. Choose Output for the following set of code :

1. static void Main(string[] args)

2. {

3.     string s1 = "Hello" + " I " + "Love" + " ComputerScience ";

4.     Console.WriteLine(s1);

5.     Console.ReadLine();

6. }

a) HelloILoveComputerScience
b) Hello I Love ComputerScience
c) Compile time error
d) Hello

Answer: b

Explanation: Here ‘+’ defined operator works as concatenation for strings.
Output : Hello I Love ComputerScience.

7. Correct way to find if contents of two strings are equal ?

a) if (s1 = s2)
b) if (s1 != s2)
c) if (strcmp (s1 ,s2))
d) if ( s1 is s2)

Answer: c

Explanation: “==” operator used to compare length of two strings and strcmp() is the inbuilt method derived from string class.

8. Which of the following statements are correct?

a) String is value type
b) String literals can contain any character literal including escape sequences
c) The equality operators are defined to compare values of string objects as well as references
d) All of the mentioned

Answer: b

9. Which of these operators can be used to concatenate two or more String objects?

a) +
b) +=
c) &
d) ||

Answer: a

Explanation: string s1 = “Hello”+ ” I ” + “Love” + ” ComputerScience “;
Console.WriteLine(s1);
Hello I Love ComputerScience.

10. The Method use to remove white space from string?

a) Split()
b) Substring()
c) Trim()
d) TrimStart()

Answer: c

Explanation: Perfectly removes a whitespace from string whereas TrimStart() removes a string of characters from the end of the string.