Runtime error handling in Compiler Design - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to identify the type of runtime error.

Compiler Design

try {
    int result = 10 / [1];
} catch (ArithmeticException e) {
    System.out.println("Runtime error: Division by zero");
}

Drag options to blanks, or click blank then click option'

A1

B0

C2

D10

Attempts:

3 left

💡 Hint

Common Mistakes

Using a non-zero number does not cause a runtime error.

The runtime error occurs when dividing by zero, so the blank should be filled with 0.

2fill in blank

medium

Complete the code to catch a null pointer exception at runtime.

Compiler Design

String text = null;
try {
    int length = text.[1]();
} catch (NullPointerException e) {
    System.out.println("Runtime error: Null pointer");
}

Drag options to blanks, or click blank then click option'

AgetLength()

Blength

Csize()

Dlength()

Attempts:

3 left

💡 Hint

Common Mistakes

Using property 'length' without parentheses causes compile error.

The method to get the length of a string is length(). Calling it on a null object causes a NullPointerException at runtime.

3fill in blank

hard

Fix the error in the code to properly handle an array index out of bounds exception.

Compiler Design

int[] numbers = {1, 2, 3};
try {
    int value = numbers[[1]];
} catch (ArrayIndexOutOfBoundsException e) {
    System.out.println("Runtime error: Index out of bounds");
}

Drag options to blanks, or click blank then click option'

A0

B2

C3

D-1

Attempts:

3 left

💡 Hint

Common Mistakes

Using valid indices does not cause runtime error.

Accessing index 3 in an array of size 3 causes an ArrayIndexOutOfBoundsException at runtime. The blank should be filled with 3 to trigger the error.

4fill in blank

hard

Fill both blanks to create a dictionary comprehension that filters runtime errors by severity.

Compiler Design

errors = {code: desc for code, desc in error_list if code [1] 400 and code [2] 500}

Drag options to blanks, or click blank then click option'

A>=

B<

C<=

D>

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong comparison operators causes incorrect filtering.

The comprehension filters codes greater than or equal to 400 and less than 500 to select runtime errors in that range.

5fill in blank

hard

Fill all three blanks to create a dictionary comprehension that maps error codes to descriptions for runtime errors only.

Compiler Design

runtime_errors = { [1]: [2] for [3] in errors.items() if 400 <= [1] < 500}

Drag options to blanks, or click blank then click option'

Acode

Bdesc

Ccode, desc

Ditem

Attempts:

3 left

💡 Hint

Common Mistakes

Using incorrect variable names causes runtime errors or syntax errors.

The comprehension uses code as key, desc as value, and code, desc as the loop variable to filter runtime errors with codes between 400 and 499.

Practice

1. What is the main purpose of runtime error handling in a program?

easy

A. To design the program's user interface

B. To manage unexpected problems that occur while the program is running

C. To improve the program's loading speed

D. To write comments in the code

Solution

1. Step 1: Understand runtime errors

   Runtime errors happen when a program runs and encounters unexpected problems like dividing by zero or missing files.

2. Step 2: Purpose of handling these errors

   Handling runtime errors helps the program respond safely without crashing, improving user experience.

3. Final Answer:

   To manage unexpected problems that occur while the program is running -> Option B

4. Quick Check:

   Runtime error handling = manage unexpected problems [OK]

Hint: Runtime errors happen during running, handle to avoid crashes [OK]

Common Mistakes:

• Confusing runtime errors with syntax errors
• Thinking error handling improves speed
• Believing error handling is for UI design

2. Which of the following is the correct syntax structure to catch runtime errors in many programming languages?

easy

A. for (error in errors) { /* handle error */ }

B. if (error) { /* handle error */ } else { /* code */ }

C. while (error) { /* handle error */ }

D. try { /* code */ } catch (error) { /* handle error */ }

Solution

1. Step 1: Identify error handling syntax

   Most languages use try-catch blocks to run code and catch errors safely.

2. Step 2: Match syntax to options

   try { /* code */ } catch (error) { /* handle error */ } shows the correct try-catch structure; others are control flow statements, not error handling.

3. Final Answer:

   try { /* code */ } catch (error) { /* handle error */ } -> Option D

4. Quick Check:

   Try-catch syntax = try { /* code */ } catch (error) { /* handle error */ } [OK]

Hint: Try-catch blocks catch errors; others are loops or conditions [OK]

Common Mistakes:

• Confusing if or loops with error handling
• Missing catch block after try
• Using wrong keywords for error handling

3. Consider this pseudocode:
try {
result = 10 / 0;
print(result);
} catch (error) {
print("Error caught");
} finally {
print("Done");
}
What will be the output when this code runs?

medium

A. Error caughtDone

B. 10Done

C. DoneError caught

D. Runtime error and no output

Solution

1. Step 1: Analyze try block

   Dividing 10 by 0 causes a runtime error, so the print(result) is skipped.

2. Step 2: Catch and finally blocks

   The catch block prints "Error caught". The finally block always runs and prints "Done".

3. Final Answer:

   Error caught
   Done -> Option A

4. Quick Check:

   Error caught then finally runs = Error caught
   Done [OK]

Hint: Error triggers catch, finally always prints last [OK]

Common Mistakes:

• Expecting result to print despite error
• Ignoring finally block output
• Thinking error stops all output

4. Identify the error in this pseudocode for runtime error handling:
try {
print("Start");
} catch {
print("Error");
}

medium

A. Catch block must come before try block

B. Missing finally block

C. Missing error parameter in catch block

D. Try block cannot have print statements

Solution

1. Step 1: Check catch block syntax

   Most languages require catch to specify an error parameter to receive the error object.

2. Step 2: Validate other parts

   Try block can have print statements, finally is optional, and catch must follow try.

3. Final Answer:

   Missing error parameter in catch block -> Option C

4. Quick Check:

   Catch needs error parameter = Missing error parameter in catch block [OK]

Hint: Catch must name error to handle it properly [OK]

Common Mistakes:

• Thinking finally block is mandatory
• Believing print can't be in try
• Reordering try and catch blocks

5. You want to write a program that reads a list of numbers and divides 100 by each number. If a division by zero occurs, it should skip that number and continue. Which runtime error handling approach is best?

hard

A. Use try-catch inside the loop to catch division errors and continue

B. Use a single try-catch around the whole loop and stop on error

C. Do not use try-catch; just check if number is zero before dividing

D. Use finally block to skip zero values

Solution

1. Step 1: Understand the problem

   We want to handle errors for each division separately and continue processing all numbers.

2. Step 2: Choose error handling approach

   Using try-catch inside the loop catches errors per division and allows continuing. A single try-catch stops on first error. Checking zero before dividing is good but not runtime error handling. Finally block is for cleanup, not skipping values.

3. Final Answer:

   Use try-catch inside the loop to catch division errors and continue -> Option A

4. Quick Check:

   Catch errors per item to continue = Use try-catch inside the loop to catch division errors and continue [OK]

Hint: Catch errors inside loop to handle each case separately [OK]

Common Mistakes:

• Stopping loop on first error
• Not using try-catch for runtime errors
• Misusing finally block for logic control