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Semester Final CS3

Last updated over 1 year ago
30 questions
1

What is output by the code below?
String[] ray;
ray = new String[4];
System.out.println( ray[0] );

1

What is output by the code below?
Integer[] ray;
ray = new Integer[4];
System.out.println( ray[3] );

1

What is output by the code below?
Integer[] ray;
ray = new Integer[4];
ray[1] = null;
ray[0] = new Integer(3);
ray[2] = new Integer(99);
System.out.println( ray[2] );

1

What is output by the code below?
Integer[] ray = {11,55,-4,909};
System.out.println( ray[3] );

1

What is output by the code below?
Double[] ray = {11.2,55.0,-4.5,909.0};
System.out.println( ray[1] );

1

What is output by the code below?
Double[] ray = {11.2,7.2,-4.5,909.0};
ray[1] = new Double(55.0);
System.out.println( ray[1] );

1

What is output by the code below?
Double[] ray = {3.2,5.7,6.3,1.9};
double x = 0;
for( double r : ray )
x += r;
System.out.println( x );

1

What is output by the code below?
Double[] ray = {3.1,5.2,6.3,1.4};
for( double r : ray )
r = 0;
System.out.println( ray[2] );

1

What is output by the code below?
String[] ray;
ray = new String[4];
ray[1] = "one";
System.out.println( ray[1] );

1

What is output by the code below?
String[] ray;
ray = new String[4];
ray[1] = "one";
ray[2] = "two";
ray[3] = "three";
System.out.println( ray[0] );

1

What do you call the condition that stops recursion?

1

What is returned the call fun(6) ?
public static int fun(int x)
{
if(x < 1)
return 1;
else
return x + fun(x - 1);
}

1

What is returned by the call fun(8) ?
public static int fun(int x)
{
if(x < 1)
return 1;
else
return x + fun(x - 1);
}

1

What is returned by the call fun(8) ?
public static int fun(int x){
if(x < 1)
return 1;
else
return x + fun(x - 2);
}

1

What is returned by the call fun(6) ?
public static int fun(int x){
if(x < 1)
return 1;
else
return x + fun(x - 2);
}

1

What is returned by the call wacky(4,6) ?
public static int wacky(int x, int y){
if(x <= 1)
return y;
else
return wacky(x - 1,y - 1) + y;
}

1

Which of the following sorts splits data into smaller lists, sorts the smaller lists, and then combines all of the sorted smaller lists back into one big list?

1

What is output by the code below?
ArrayList<Integer> r;
r = new ArrayList<Integer>();
r.add(1);
r.add(2);
r.add(3);
out.println( r.indexOf(100) );

1

What type of sort is funSort()?
public static void funSort( int[] ray )
{
for(int i=0; i< ray.length-1; i++)
{
int max = i;
for(int j = i+1; j<ray.length; j++)
{
if( ray[j] > ray[max] )
max = j;
}
if( max != i){
int temp = ray[max];
ray[max] = ray[i];
ray[i] = temp;
}
}
}

1

For the code at right to correctly implement a linear search, which of the following would correctly fill < blank 1 > ?
public static int find( ArrayList list, Object param )
{
for(int i=0; i < list.size(); i++)
{
if( list.get(i).equals(param) )
return i;
}
< blank 1 >
}

1

How many times would help() be called before list was sorted?
public void sort( int[] list, int front, int back)
{
int mid = (front+back)/2;
if( mid==front) return;
sort(list, front, mid);
sort(list, mid, back);
help(list, front, back);
}
private void help(int[] list, int front, int back)
{
int[] temp = new int[back-front];
int i = front, j = (front+back)/2, k =0;
int mid =j;
while( i<mid && j<back)
{
if(list[i]< list [j])
temp[k++]= list[i++];
else
temp[k++]= list[j++];
}
while(i<mid)
temp[k++]= list[i++];
while(j<back)
temp[k++]= list[j++];
for(i = 0; i<back-front; ++i)
list[front+i]=temp[i];
}
//code in the main
int[] list = {39,6,11,23,18,3,20,5,57};
sort(list, 0, list.length);

1

If ray is storing 10 elements, what is the maximum number of swaps funSort() could make in order to put the elements in order?
public static void funSort( int[] ray )
{
for(int i=0; i< ray.length-1; i++)
{
int max = i;
for(int j = i+1; j < ray.length; j++)
{
if( ray[j] > ray[max] )
max = j;
}
if( max != i){
int temp = ray[max];
ray[max] = ray[i];
ray[i] = temp;
}
}
}

1

If funSearch() will only work on sorted data, what type of sort is funSearch()?
public static int funSearch( int[] list, int val )
{
int len=list.length;
int bot=0, top=len-1;
int middle=0;
while( bot <= top )
{
middle=(bot+top)/2;
if (list[middle] == val)
return middle;
else
if(list[middle]>val)
top=middle-1;
else
bot=middle+1;
}
return -1;
}

1

funSort() will put the items in ray in what type of order?
public static void funSort( int[] ray )
{
for(int i=0; i< ray.length-1; i++)
{
int max = i;
for(int j = i+1; j < ray.length; j++)
{
if( ray[j] > ray[max] )
max = j;
}
if( max != i){
int temp = ray[max];
ray[max] = ray[i];
ray[i] = temp;
}
}
}

1

Which sort is shown below?
public void sort( int[] list, int front, int back)
{
int mid = (front+back)/2;
if( mid==front) return;
sort(list, front, mid);
sort(list, mid, back);
help(list, front, back);
}
private void help(int[] list, int front, int back)
{
int[] temp = new int[back-front];
int i = front, j = (front+back)/2, k =0;
int mid =j;
while( i<mid && j<back)
{
if(list[i]< list [j])
temp[k++]= list[i++];
else
temp[k++]= list[j++];
}
while(i<mid)
temp[k++]= list[i++];
while(j<back)
temp[k++]= list[j++];
for(i = 0; i<back-front; ++i)
list[front+i]=temp[i];
}

1

What would be the value of list after four passes of the help() method?
public void sort( int[] list, int front, int back)
{
int mid = (front+back)/2;
if( mid==front) return;
sort(list, front, mid);
sort(list, mid, back);
help(list, front, back);
}
private void help(int[] list, int front, int back)
{
int[] temp = new int[back-front];
int i = front, j = (front+back)/2, k =0;
int mid =j;
while( i<mid && j<back)
{
if(list[i]< list [j])
temp[k++]= list[i++];
else
temp[k++]= list[j++];
}
while(i<mid)
temp[k++]= list[i++];
while(j<back)
temp[k++]= list[j++];
for(i = 0; i<back-front; ++i)
list[front+i]=temp[i];
}
//code in the main
int[] list = {39,6,11,23,18,3,20,5,57};
sort(list, 0, list.length);

1

What is returned by the call wacky(2,6) ?
public static int wacky(int x, int y)
{
if(x <= 1)
return y;
else
return wacky(x - 1,y - 1) + y;
}

1

What is returned by the call fun(1) ?
public static int fun(int x)
{
if(x < 1)
return 1;
else
return x - fun(x - 3);
}

1

What is returned by the call wacky(5,5) ?
public static int wacky(int x, int y){
if(x <= 1)
return y;
else
return wacky(x - 1,y - 1) + y;
}

1

What is returned by the call fun(10) ?
public static int fun(int x)
{
if (x < 1)
return x;
else
return x + fun(x - 2);
}