AP Computer Science Midterm Exam

The value is actually 11

The output of the code above would be "put". The substring method in Java returns a new string that is a substring of the original string. In this case, the substring starts at index 3 (inclusive) and ends at index 6 (exclusive), so it includes the characters at indices 3, 4, and 5, which are "p", "u", and "t" respectively. Therefore, the correct answer is False.

The given declaration states that the variable FEE is declared as final, which means its value cannot be changed once it is assigned. This is indicated by the keyword "final" before the data type. Since the value of FEE is set to 0.50, it cannot be altered later in the program. If there is any attempt to modify the value of FEE, the compiler will catch it and throw an error. Therefore, the statement "The value of the variable FEE cannot subsequently be altered in the program, and any attempt to do so will be caught by the compiler" is true.

A constructor is a class method that is automatically called whenever an object of that class is created. It is responsible for initializing the object's state and allocating memory for it. The constructor typically takes parameters to set initial values for the object's attributes. By calling the constructor, the object is created and ready for use.

The given code will not swap the contents of the integer variables x and y. This is because the variable z is not assigned any value before it is assigned to x. Therefore, when z is assigned to y, and then x is assigned to z, the original values of x and y will not be preserved and the swap will not occur.

The expression !(a||b) represents the negation of the logical OR operation between variables a and b. This means that the expression will be true only if both a and b are false. On the other hand, the expression (!a)&&(!b) represents the logical AND operation between the negations of variables a and b. This expression will also be true only if both a and b are false. Since both expressions have the same conditions for being true, they are equivalent. Therefore, the answer is true.

The scope of a variable refers to the section of the program in which the variable exists. It determines the visibility and accessibility of the variable within the program. The scope defines where the variable can be used and accessed, and it helps in avoiding conflicts and maintaining the integrity of the program.

The result of (x == y) is false because the == operator checks for reference equality. In this case, x and y are two different objects in memory. x is referencing the string "Smile" while y is referencing null. Since they are not referencing the same object, the comparison evaluates to false.

The given code calculates the value of variable "a" using the expression "b * (-c + 2) / 7". Here, b is 6 and c is 11. So, substituting the values, the expression becomes 6 * (-11 + 2) / 7. Simplifying further, we have 6 * (-9) / 7, which is -54 / 7. Dividing -54 by 7 gives us approximately -7.71428. Therefore, the value stored in variable "a" is -7.71428.

The code segment uses the substring() method to extract a portion of the string S. The method takes two parameters, the starting index (inclusive) and the ending index (exclusive). In this case, the starting index is 1 and the ending index is 5. Therefore, the substring that is extracted from S is "Love". The print statement then outputs this substring.

The given method checks if the first character of the string is equal to any other character in the string. If it is, then it returns true. If not, it continues checking until the end of the string and then returns false.

For the first string "dttd", the first character 'd' occurs again at index 3, so the method correctly returns true.

For the second string "xxxx", the first character 'x' occurs again at index 1, so the method correctly returns true.

For the third string "look", the first character 'l' does not occur again in the string, so the method incorrectly returns false.

Therefore, the method correctly returns true for the strings I and II.

Condition 3 states that x is less than y and greater than 0. Since x is 8 and y is 3, this condition is false because 8 is not less than 3. Therefore, the correct answer is that only condition 3 is false.

Segment II and III correctly define a Point variable that represents the point (3,5). In Segment II, a Point object is created using the constructor Point(int x, int y), and then the SetX and SetY methods are used to set the x and y coordinates to 3 and 5 respectively. In Segment III, a Point object is directly created using the constructor Point(int x, int y) with the values 3 and 5 passed as arguments.

The given statement is false. In Java, when evaluating a boolean expression with the "&&" operator, the second sub-expression is only evaluated if the first sub-expression is true. This is known as short-circuit evaluation. Therefore, if the first sub-expression (num >= 0) is false, the second sub-expression (num

The given code will throw an exception because we are trying to access the length of a null object (y). Since y is null, it does not have a length property, resulting in a NullPointerException.

The method "boo" takes two integers, subtracts 2 from the first integer (x) and increments the second integer (y) by 1. It then returns the product of the updated x and y values. In the given code, x is 7 and y is -3.
First, y is added to x, resulting in 7 + (-3) = 4.
Then, the method "boo" is called with y as the first argument and x as the second argument.
Inside the "boo" method, x becomes -5 (subtracting 2 from y) and y becomes 0 (incrementing y by 1).
The return value of the "boo" method is -5 * 0 = 0.
Finally, 4 + 0 = 4, so the value of z is 4.

In option C, the code segment correctly changes P to represent y,x. It creates a temporary variable tmp and assigns it the value of P.myX. Then, it assigns P.myY to P.myX and finally assigns tmp to P.myY. This effectively swaps the values of P.myX and P.myY, resulting in P representing y,x.

The swap method does not modify the original strings x and y because strings are immutable in Java. Therefore, any modifications made inside the method do not affect the original variables. As a result, x and y remain unchanged after calling the sillyStrings method.

An instance of StaticExample is created with a and initialized with a value of 12. At this point, the static variable x is set to 12.

Another instance b is created and initialized with a value of 5. The static variable x is updated to 5, which affects all instances.

The incr() method is called on instance a (which has x set to 5 now), incrementing x by 1. Therefore, the value of z after the third statement is executed is 6.

The variable "x" in the class StaticExample is declared as a static variable. Static variables are shared among all instances of a class. Therefore, regardless of the number of objects created (in this case, 4 objects), there will only be one instance of the static variable "x". So, the answer is 0.