Final Exam Practice Answers 1 Implement method public static Cat upsideDownBackwards Cat source int numRows source length Cat temp new Cat numRows int currRow numRows 1 for int row 0 row numRows row currRow int numCols source row length temp currRow new Cat numCols int currCol numCols 1 for int col 0 col numCols col currCol temp currRow currCol new Cat source row col return temp 2 Determine the output a f Hello b f c f null A C D G B C D G C E G 3 Define a switch switch value case 3 str x break case 6 str w break case 0 case 1 case 2 case 4 str A break default str B break 1 4 a b c d e f g Give results Mammal p Mammal c Works Fine Dog q Dog a Compiles but Throws an Exception Mammal r c Works Fine Dog s a Will NOT compile Dog t Dog x Works Fine Dog u x Will NOT compile For this part assume that the Dog class has an instance method called bark which is not implemented in the Mammal class x bark Will NOT compile h Suppose you add an instance method to the Mammal class called grow and that you override that method in the Dog class Consider the code below Which grow method will be called x grow CIRCLE ONE Mammal Dog 5 Indicate what is on the stack and what is on the heap after each of the following statements draw a picture Integer x new Integer 5 x is on the stack pointing at an integer object that contains a 5 int a 7 a is put on the stack with the value 7 on the stack Integer b new Integer 1 new Integer 5 b is put on the stack with a reference to a 2 element array on the heap the first element of that array is a reference to another space on the heap that is an Integer that contains a 1 the second element of that array is a reference to another space on the heap that is an Integer that contains a 5 Integer c b c is put on the stack it is a reference pointing to the same space on the heap as where b is pointing to Integer d new Integer b length d is put on the stack pointing to a 2 element array distinct from b s the elements of the array are null for int i 0 i b length i d i b i the elements of the array pointed to by d now point to the elements of the array pointed to by b they are distinct arrays but share the values int e 8 9 e comes on to the stack pointing to a two element array on the heap the 8 and 9 are directly in that array not pointed to by it 6 Assume you have the class MyClass as defined below public class MyClass private Obj1 list1 private ArrayList Obj2 list2 a Write a copy constructor for the MyClass public MyClass MyClass other list1 new Obj1 other list1 length for int row 0 row other list1 length row list1 row new Obj1 other list1 row length for int col 0 col other list1 row length col list1 row col new Obj1 other list1 row col list2 new ArrayList Obj2 for Obj2 temp other list2 list2 add new Obj2 temp 2 b Write a equals for the MyClass two MyClass objects are considered equal if the contents of the array is exactly the same and in the order and the objects of the arrayLists are exactly the same and in the same order public boolean equals Object other if other null return false else if other getClass getClass return false else MyClass local MyClass other if list1 length other list1 length list2 size other list2 size return false else for int row 0 row list1 length row if list1 row length other list1 row length return false for int col 0 col list1 row length col if list1 row col equals other list1 row col return false for int cur 0 cur list2 size cur if list2 get cur equals other list2 get cur return false return true c Write a method which returns the largest int based on the individual getValues in the array list1 call it largestInArray Return a 1 if there is nothing in the array public int largestInArray if list1 length 0 return 1 int largestSoFar 1 for int row 0 row list1 length row for int col 0 col list1 row length col if list1 row col getValue largestSoFar largestSoFar list1 row col getValue return largestSoFar d Write a method which returns the largest int based on the individual getValues in the ArrayList list2 call it largestInList Return a 1 if there is nothing in the ArrayList public int largestInList if list2 size 0 3 return 1 int largestSoFar 1 for Obj2 temp list2 if temp getValue largestSoFar largestSoFar temp getValue return largestSoFar e Write a method that uses the two previous methods to return a single integer which is the largest of the whole class Returns a 1 if and only if they are both empty public int largestWhole return largestInArray largestInList largestInArray largestInList f Write a sum method that returns the sum of all getValues in both data members public int sumAll int sum 0 for int row 0 row list1 length row for int col 0 col list1 row length col sum list1 row col getValue for Obj2 temp list2 sum temp getValue return sum g Write a toString method that returns the first value the 0 0 element of the array followed by the first item in the ArrayList If either is empty there are no objects inside return the string empty public String toString if list2 size 0 return empty if list1 length 0 return empty boolean allEmpty true for Obj1 row list1 if row length 0 allEmpty false if allEmpty return empty if list1 0 length 0 return empty return list1 0 0 list2 get 0 4 h Write a method that returns a Stack of all objects on the array order does not matter but all items present in the array must be on a Stack that is returned as the return value of the method public Stack Obj1 stackIt Stack Obj1 temp new Stack Obj1 for int row 0 row list1 length row for int col 0 col list1 row length col temp push new Obj1 list1 row col return temp i Write a method that uses a for loop to increaseValue of all of the objects in list1 Rewrite using for each Randomly 5 is chosen as the amount to raise it by public void increaseArrFirstWay for int row 0 row list1 length row for int col 0 col list1 row length col list1 row col increaseValue 5 public void increaseArrSecondWay for Obj1 row list1 for Obj1 temp row temp increaseValue 5 j Write a method that uses a for loop to increaseValue of all of the objects in list2 Rewrite with for each Randomly …
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