1. Which of the following is the correct syntax for an if statement in C#?
a) if (condition) { /* code */ }
b) if condition { /* code */ }
c) if (condition) then { /* code */ }
d) if condition then { /* code */ }
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Answer:
a) if (condition) { /* code */ }
Explanation:
The correct syntax for an if statement in C# includes parentheses around the condition and curly braces for the code block.
2. How do you add an else statement in C#?
a) if (condition) { /* code if true */ } else { /* code if false */ }
b) if (condition) { /* code if true */ } otherwise { /* code if false */ }
c) if (condition) then { /* code if true */ } else { /* code if false */ }
d) if condition { /* code if true */ } else { /* code if false */ }
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Answer:
a) if (condition) { /* code if true */ } else { /* code if false */ }
Explanation:
The else statement is added after the closing brace of the if statement's code block.
3. What is the purpose of the else if statement in C#?
a) To execute code if the previous if condition is true
b) To execute code if the previous if condition is false, and a new condition is true
c) To execute code regardless of the previous if condition
d) None of the above
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Answer:
b) To execute code if the previous if condition is false, and a new condition is true
Explanation:
The else if statement allows for additional conditions to be checked if the previous if condition is false.
4. Can the else statement in C# exist without the preceding if statement?
a) Yes, else can exist on its own
b) No, else must always follow an if
c) Yes, but only if there are no conditions
d) No, but it can follow an else if
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Answer:
b) No, else must always follow an if
Explanation:
The else statement is always paired with an if statement. It cannot exist independently.
5. How many else if statements can you have in a single if statement block in C#?
a) Only one
b) Up to five
c) As many as needed
d) None, else if is not allowed in C#
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Answer:
c) As many as needed
Explanation:
You can have as many else if statements as necessary in an if statement block in C#.
6. What is the result of using nested if statements in C#?
a) Increases code complexity and readability
b) Allows the checking of another condition within an if or else if block
c) Causes a syntax error
d) Reduces the efficiency of the code
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Answer:
b) Allows the checking of another condition within an if or else if block
Explanation:
Nested if statements are used to check additional conditions within an if or else if block.
7. Which of the following demonstrates the use of multiple conditions in an if statement in C#?
a) if (condition1 && condition2) { /* code */ }
b) if condition1 and condition2 { /* code */ }
c) if (condition1 + condition2) { /* code */ }
d) if condition1 & condition2 { /* code */ }
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Answer:
a) if (condition1 && condition2) { /* code */ }
Explanation:
The && operator is used to combine multiple conditions in an if statement.
8. What is the correct way to write an if statement without a code block in C#?
a) if (condition) statement;
b) if (condition) -> statement;
c) if (condition) : statement;
d) if condition -> statement;
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Answer:
a) if (condition) statement;
Explanation:
In C#, you can write a single statement after the if condition without using curly braces.
9. How does C# handle the evaluation of conditions in an if-else if-else block?
a) All conditions are evaluated regardless of their outcome
b) Evaluates conditions until one is true, then skips the remaining
c) Evaluates only the first and last conditions
d) Evaluates all if conditions but skips the else
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Answer:
b) Evaluates conditions until one is true, then skips the remaining
Explanation:
In an if-else if-else block, C# stops evaluating further conditions as soon as one condition evaluates to true.
10. What will happen if the condition in an if statement is always true?
a) The program will enter an infinite loop
b) The if block will be ignored
c) The program will throw a runtime error
d) The if block will execute every time
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Answer:
d) The if block will execute every time
Explanation:
If the condition in an if statement is always true, the code inside the if block will execute each time the condition is checked.
11. In C#, what type of values can be used as conditions in an if statement?
a) Only boolean values
b) Integers
c) Any type, as long as it's not null
d) Boolean values and expressions that result in a boolean
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Answer:
d) Boolean values and expressions that result in a boolean
Explanation:
In C#, conditions in if statements must be boolean values or expressions that evaluate to a boolean.
12. Which of the following is not a valid way to write an if statement in C#?
a) if (1 == 1) { /* code */ }
b) if (true) { /* code */ }
c) if (false) { /* code */ } else { /* code */ }
d) if (x = 5) { /* code */ }
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Answer:
d) if (x = 5) { /* code */ }
Explanation:
The expression 'x = 5' is an assignment, not a comparison. It's not a valid condition for an if statement.
13. What happens if an if condition in C# evaluates to false and there is no else block?
a) The program throws an error
b) The if block executes with a default value
c) The program exits
d) The if block is skipped
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Answer:
d) The if block is skipped
Explanation:
If the if condition evaluates to false and there is no else block, the code inside the if block is skipped.
14. Is it possible to have an if statement without an else statement in C#?
a) Yes, it is possible
b) No, else is mandatory
c) Only in certain conditions
d) Yes, but only inside a loop
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Answer:
a) Yes, it is possible
Explanation:
It is perfectly valid to have an if statement without an accompanying else statement.
15. What does the following code do in C#?
if (condition)
{
/* code block 1 */
}
else if (anotherCondition)
{
/* code block 2 */
}
else
{
/* code block 3 */
}
a) Executes code block 1 if condition is true, otherwise checks anotherCondition
b) Always executes code block 3
c) Executes each code block in order
d) Executes code block 1 and then code block 3
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Answer:
a) Executes code block 1 if condition is true, otherwise checks anotherCondition
Explanation:
If condition is true, code block 1 executes. If not, it checks anotherCondition, executing code block 2 if true, and code block 3 if both conditions are false.