C# Strings MCQ

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1. How do you concatenate strings in C#?

a) Using the '+' operator

b) Using the '&' operator

c) Using the concat() method

d) Using the append() method

Answer:

a) Using the '+' operator

Explanation:

In C#, strings are commonly concatenated using the '+' operator.

2. What method is used to compare two strings for equality in C#?

a) equals()

b) isEqual()

c) CompareTo()

d) Compare()

Answer:

a) equals()

Explanation:

The equals() method is used to compare two strings for equality in C#.

3. Which method in the String class returns the length of a string in C#?

a) Length

b) Count

c) Size

d) GetLength

Answer:

a) Length

Explanation:

The Length property of the String class is used to get the length of a string in C#.

4. How can you convert a string to uppercase in C#?

a) toUpperCase()

b) ToUpper()

c) Uppercase()

d) MakeUpper()

Answer:

b) ToUpper()

Explanation:

The ToUpper() method is used to convert a string to uppercase in C#.

5. What is the output of the following code in C#?

a) Hello,

b) World!

c) ello, World!

d) , World!

Answer:

b) World!

Explanation:

The Substring(7) method returns a new string starting from the 7th index of the original string.

6. What is the character used to denote a verbatim string in C#?

a) @

b) #

c) $

d) %

Answer:

a) @

Explanation:

In C#, the '@' character is used before a string literal to denote a verbatim string.

7. How do you split a string on specific characters in C#?

a) Using the Split() method

b) Using the Divide() method

c) Using the Break() method

d) Using the Cut() method

Answer:

a) Using the Split() method

Explanation:

The Split() method is used to split a string into an array of substrings based on specific characters.

8. What does the Trim() method do in C#?

a) Removes all whitespace

b) Removes whitespace from the start and end of a string

c) Trims a string to a specified length

d) Removes specified characters from a string

Answer:

b) Removes whitespace from the start and end of a string

Explanation:

The Trim() method is used to remove all leading and trailing white-space characters from a string.

9. How do you determine if a string starts with a specific substring in C#?

a) StartsWith()

b) BeginsWith()

c) HasPrefix()

d) LeadingString()

Answer:

a) StartsWith()

Explanation:

The StartsWith() method is used to check if a string starts with a specific substring.

10. What is the result of string concatenation using the following code in C#?

a) HelloWorld

b) Hello World

c) Hello+World

d) Hello_World

Answer:

b) Hello World

Explanation:

The '+' operator is used to concatenate strings with a space in between.

11. How do you find the position of a substring within a string in C#?

a) Index()

b) FindIndex()

c) Locate()

d) IndexOf()

Answer:

d) IndexOf()

Explanation:

The IndexOf() method is used to find the position of a substring within a string.

12. Which method is used to replace a specified substring with another substring in a string in C#?

a) Change()

b) Switch()

c) Replace()

d) Modify()

Answer:

c) Replace()

Explanation:

The Replace() method is used to replace all occurrences of a specified substring with another substring in a string.

13. What is the output of the following code in C#?

a) S

b) h

c) a

d) C

Answer:

b) h

Explanation:

String indexing in C# is zero-based, so text[2] refers to the third character, which is 'h'.

14. How do you convert a string to a number in C#?

a) int.Parse()

b) Convert.ToInt32()

c) StringToNumber()

d) Both a and b

Answer:

d) Both a and b

Explanation:

Both int.Parse() and Convert.ToInt32() methods can be used to convert a string to a number.

15. What does the IsNullOrEmpty method do in C#?

a) Checks if a string is empty or consists of only whitespace characters

b) Checks if a string is null or has a length of zero

c) Checks if a string is null or consists of only whitespace characters

d) Checks if a string is null or empty array

Answer:

b) Checks if a string is null or has a length of zero

Explanation:

The IsNullOrEmpty method checks whether a string is null or its length is zero.

16. How do you format a string in C# using placeholders?

a) Using the Format() method

b) Using string interpolation

c) Using the Concat() method

d) Both a and b

Answer:

d) Both a and b

Explanation:

Both the String.Format() method and string interpolation can be used to format strings using placeholders in C#.

17. What is the escape sequence used for a new line in C#?

a) \\n

b) \n

c) /n

d) //n

Answer:

b) \n

Explanation:

The '\n' escape sequence is used to represent a new line in C#.

18. How can you check if a string contains a specific substring in C#?

a) Contains()

b) Has()

c) Includes()

d) Find()

Answer:

a) Contains()

Explanation:

The Contains() method is used to check if a string contains a specific substring.

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