CS 10: Introduction to Computer Programming

In-Class Examination 2

Closed-Book, 50 minutes, Fall 1997

General Instructions

Before you answer any questions, write your name, perm number, and discussion section on your answer booklet.
Read each question carefully.
Make sure that you clearly understand a question before answering it.
Please put your answer to each question on its own page in your blue-book.
Answers that do not show work will not get partial credit.
You may wish to work out an answer on scratch paper before writing it on your answer page; answers that are difficult to read may lose points for that reason.

Question	Value
1	15
2	15
3	15
4	15
5	20
6	20
Total	100

1. Write a java expression whose value is a random integer in the set [start, start+1, start+2, ..., end], for int variables start and end. Assume that end > start. If this cannot be done, explain why.

2. Write a java statement that assigns 7 to int variable j, if the value of int variable i is evenly divisible by 2 and 3 and is evenly divisible by neither 5 nor 7, and assigns -7 to int variable j otherwise. Do not nest if statements.

3. Convert the following code fragment to an equivalent one that uses a switch statement. If this cannot be done, explain why.

        // apply tool
        if (tool == 1)
            g.drawLine(x, y, x + width, y + height);
        else if (tool == 2)
            g.drawRect(x, y, width, height);
        else if (tool == 3)
            g.fillRect(x, y, width, height);
        else if (tool == 4)
            g.drawOval(x, y, width, height);
        else if (tool == 5)
            g.fillOval(x, y, width, height);

4. Write a java method, implies, that takes 2 boolean (true or false) arguments, p and q, and returns true if p is false or q is true.

5. Write a java method, summer, that takes an argument, data, that is an int array, and an argument top, that is an int, and returns, as a float, the sum of the odd elements of the array, data, (which starts with element 0) whose indices are less than top.

6. Write a java method, maximizer, that takes 2 int arguments: a doubly-subscripted array, table, and an array, max. The method puts the maximum element of row i of table into element i of max.