What is the result of the program?
❌ A. -1
✅ B. 9
❌ C. 81
❌ D. Compiler error on line 9.
❌ E. Compiler error on a different line
Explanation:
Since Java is pass-by-value and the variable on line 8 never gets reassigned, it stays as 9. In the method square, x starts as 9. y becomes 81 and then x gets set to –1. Line 9 does set result to 81. However, we are printing out value and that is still 9.
❌ A. -1
✅ B. 9
❌ C. 81
❌ D. Compiler error on line 9.
❌ E. Compiler error on a different line
Explanation:
Since Java is pass-by-value and the variable on line 8 never gets reassigned, it stays as 9. In the method square, x starts as 9. y becomes 81 and then x gets set to –1. Line 9 does set result to 81. However, we are printing out value and that is still 9.
Assuming weather is a well-formed nonempty array, which code snippet, when inserted independently into the blank in the following code, prints all of the elements of weather? (Choose all that apply.)
❌ A. int i = weather.length; i > 0; i--
✅ B. int i = 0; i <= weather.length - 1; ++i
❌ C. var w : weather
✅ D. int i = weather.length - 1; i >= 0; i--
❌ E. int i = 0, int j = 3; i < weather.length; ++i
❌ F. int i = 0; ++i < 10 && i < weather.length;
❌ G. None of the above
Explanation:
Option A is incorrect because on the first iteration it attempts to access weather[weather.length] of the nonempty array, which causes an ArrayIndexOutOfBoundsException to be thrown. Option B is correct and will print the elements in order. It is only a slight modification of a common for loop, with i<weather.length replaced with an equivalent i<=weather.length-1. Option C is incorrect because the snippet creates a compilation problem in the body of the for loop, as i is undefined in weather[i]. For this to work, the body of the for-each loop would have to be updated as well. Option D is also correct and is a common way to print the elements of an array in reverse order. Option E does not compile and is therefore incorrect. You can declare multiple elements in a for loop, but the data type must be listed only once, such as in for(int i=0, j=3; ...). Finally, option F is incorrect because the first element of the array is skipped. The loop update operation is optional, so that part compiles, but the increment is applied as part of the conditional check for the loop. Since the conditional expression is checked before the loop is executed the first time, the first value of i used inside the body of the loop will be 1.
❌ A. int i = weather.length; i > 0; i--
✅ B. int i = 0; i <= weather.length - 1; ++i
❌ C. var w : weather
✅ D. int i = weather.length - 1; i >= 0; i--
❌ E. int i = 0, int j = 3; i < weather.length; ++i
❌ F. int i = 0; ++i < 10 && i < weather.length;
❌ G. None of the above
Explanation:
Option A is incorrect because on the first iteration it attempts to access weather[weather.length] of the nonempty array, which causes an ArrayIndexOutOfBoundsException to be thrown. Option B is correct and will print the elements in order. It is only a slight modification of a common for loop, with i<weather.length replaced with an equivalent i<=weather.length-1. Option C is incorrect because the snippet creates a compilation problem in the body of the for loop, as i is undefined in weather[i]. For this to work, the body of the for-each loop would have to be updated as well. Option D is also correct and is a common way to print the elements of an array in reverse order. Option E does not compile and is therefore incorrect. You can declare multiple elements in a for loop, but the data type must be listed only once, such as in for(int i=0, j=3; ...). Finally, option F is incorrect because the first element of the array is skipped. The loop update operation is optional, so that part compiles, but the increment is applied as part of the conditional check for the loop. Since the conditional expression is checked before the loop is executed the first time, the first value of i used inside the body of the loop will be 1.
Given the method, how many lines contain compilation errors?
❌ A. None, the code compiles without issue
❌ B. 1
❌ C. 2
❌ D. 3
✅ E. 4
❌ F. 5
❌ G. 6
❌ H. The code compiles but may produce an error at runtime
Explanation
This code contains numerous compilation errors, making options A and H incorrect. All of the compilation errors are contained within the switch statement. The default statement is fine and does not cause any issues. The first case statement does not compile, as continue cannot be used inside a switch statement. The second case statement also does not compile. While the thursday variable is marked final, it is not a compile-time constant required for a switch statement, as any int value can be passed in at runtime. The third case statement is valid and does compile, as break is compatible with switch statements. The fourth case statement does not compile. Even though Sunday is effectively final, it is not a compile-time constant. If it were explicitly marked final, then this case statement would compile. Finally, the last case statement does not compile because DayOfWeek.MONDAY is not an int value. While switch statements do support enum values, each case statement must have the same data type as the switch variable otherDay, which is int. Since exactly four lines do not compile, option E is the correct answer.
❌ A. None, the code compiles without issue
❌ B. 1
❌ C. 2
❌ D. 3
✅ E. 4
❌ F. 5
❌ G. 6
❌ H. The code compiles but may produce an error at runtime
Explanation
This code contains numerous compilation errors, making options A and H incorrect. All of the compilation errors are contained within the switch statement. The default statement is fine and does not cause any issues. The first case statement does not compile, as continue cannot be used inside a switch statement. The second case statement also does not compile. While the thursday variable is marked final, it is not a compile-time constant required for a switch statement, as any int value can be passed in at runtime. The third case statement is valid and does compile, as break is compatible with switch statements. The fourth case statement does not compile. Even though Sunday is effectively final, it is not a compile-time constant. If it were explicitly marked final, then this case statement would compile. Finally, the last case statement does not compile because DayOfWeek.MONDAY is not an int value. While switch statements do support enum values, each case statement must have the same data type as the switch variable otherDay, which is int. Since exactly four lines do not compile, option E is the correct answer.
What is the result of the code snippet?
❌ A. 11
❌ B. 13
✅ C. 23
❌ D. 33
❌ E. 50
❌ F. The code will not compile because of line 7
Explanation:
Prior to the first iteration, sing = 8, squawk = 2, and notes = 0. After the iteration of the first loop, sing is updated to 7, squawk to 4, and notes to the sum of the new values for sing + squawk, 7 + 4 = 11. After the iteration of the second loop, sing is updated to 6, squawk to 6, and notes to the sum of itself, plus the new values for sing + squawk, 11 + 6 + 6 = 23. On the third iteration of the loop, sing > squawk evaluates to false, as 6 > 6 is false. The loop ends and the most recent value of sing, 23, is output, so the correct answer is option C.
❌ A. 11
❌ B. 13
✅ C. 23
❌ D. 33
❌ E. 50
❌ F. The code will not compile because of line 7
Explanation:
Prior to the first iteration, sing = 8, squawk = 2, and notes = 0. After the iteration of the first loop, sing is updated to 7, squawk to 4, and notes to the sum of the new values for sing + squawk, 7 + 4 = 11. After the iteration of the second loop, sing is updated to 6, squawk to 6, and notes to the sum of itself, plus the new values for sing + squawk, 11 + 6 + 6 = 23. On the third iteration of the loop, sing > squawk evaluates to false, as 6 > 6 is false. The loop ends and the most recent value of sing, 23, is output, so the correct answer is option C.
What is the output of the code snippet?
❌ A. 7
❌ B. 9
❌ C. 10
❌ D. 11
❌ E. 15
❌ F. The code will not compile because of line 6
✅ G. The code does not compile for a different reason
Explanation:
This example may look complicated, but the code does not compile. Line 8 is missing the required parentheses around the boolean conditional expression. Since the code does not compile and it is not because of line 6, option G is the correct answer. If line 8 was corrected with parentheses, then the loop would be executed twice, and the output would be 11.
❌ A. 7
❌ B. 9
❌ C. 10
❌ D. 11
❌ E. 15
❌ F. The code will not compile because of line 6
✅ G. The code does not compile for a different reason
Explanation:
This example may look complicated, but the code does not compile. Line 8 is missing the required parentheses around the boolean conditional expression. Since the code does not compile and it is not because of line 6, option G is the correct answer. If line 8 was corrected with parentheses, then the loop would be executed twice, and the output would be 11.
What is the result of the code snippet?
❌ A. great
❌ B. great good
❌ C. good
❌ D. not good
❌ E. The code does not compile because the data type of one or more case statements does not match the data type of the switch variable
✅ F. None of the above
Explanation:
The code does not compile, although not for the reason specified in option E. The second case statement contains invalid syntax. Each case statement must have the keyword case—in other words, you cannot chain them with a colon (:) as shown in case 'B' : 'C' :. For this reason, option F is the correct answer. If this line were fixed to add the keyword case before 'C', then the rest of the code would have compiled and printed great good at runtime.
❌ A. great
❌ B. great good
❌ C. good
❌ D. not good
❌ E. The code does not compile because the data type of one or more case statements does not match the data type of the switch variable
✅ F. None of the above
Explanation:
The code does not compile, although not for the reason specified in option E. The second case statement contains invalid syntax. Each case statement must have the keyword case—in other words, you cannot chain them with a colon (:) as shown in case 'B' : 'C' :. For this reason, option F is the correct answer. If this line were fixed to add the keyword case before 'C', then the rest of the code would have compiled and printed great good at runtime.