# AP Computer Science

Agenda:

## Monday (3/9/20)

Agenda:

• Recursion quiz
• APCS FRQ 2019 #3 grading rubric
• Merge sort
• Possible MC question where they ask you to trace a merge sort execution
• Quick...
1. Create a two dimensional array of type double (4 x 6)
2. Populate the 2D array with random numbers from 0 to 100
3. Write a nested for loop that sums the entire 2D array and calculates the average

Homework:

• APCS FRQ 2019 #4 (22 minutes)

## Thursday (3/5/20)

Warmup:

```Given the following method declaration, which of the following is printed as the result of the call mystery(1234)?

//precondition:  x >=0
public static void mystery (int x)
{
System.out.print(x % 10);

if ((x / 10) != 0)
{
mystery(x / 10);
}
System.out.print(x % 10);
}

(a) 1441
(b) 43211234
(c) 3443
(d) 12344321
(e) Many digits are printed due to infinite recursion.
```

Agenda:

• Finish APCS FRQ 2019 #2 (5 minutes)
• Recursion quiz on Monday (3/9/19)
• Recursion review & HW questions?
• Recursion practice problems
• Write a recursive method that returns the sum of all the numbers from N down to 1: int sum(int N)
• Write a recursive method that prints every other letter of a string: void printSkipping(String s)
• Write a recursive method that returns true if a particular character is in the String: boolean findChar(char ch, String s)

Homework:

• APCS FRQ 2019 #3 (22 minutes)

## Tuesday (3/3/20)

• Super Tuesday (no school for students)