Exam Questions. How to Answer

Transcription

1 Exam Questions How to Answer

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3 This flowchart asks the user for their desired download speed. Then, it prints the cost of the service. Write the code that would result from this flowchart. Make sure that the code is efficient. Start Get Mpbs >= 1000 F F F >= 300 >= 150 Cost is $69.99 T T T Cost is $ Cost is $94.99 Cost is $84.99 End

4 Write a method that, when given a download speed in as a parameter, returns the corresponding cost of the service. There should be no input or output in the method. Download Speed Up to 1000 Up to 300 Up to 150 Up to 75 Cost $ $94.99 $84.99 $69.00

5 Write the code for the actionperformed Method of the Internet Cost Calculator using the cost guidelines given. Download Speed? () Evaluate The cost is $XX.XX speed answer Download Speed Up to 1000 Up to 300 Up to 150 Up to 75 Cost $ $94.99 $84.99 $69.00

6 Create two arrays. One should hold the Download Speeds. The other, the cost. Download Speed Up to 1000 Up to 300 Up to 150 Up to 75 Cost $ $94.99 $84.99 $69.00 Print both arrays in a table format. Write a program that finds the average cost. Write a program that asks for the speed and prints out the cost.

7 Exam Review Questions you asked.

8 Bubble sort Bin sort Selection sort

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10 for (int j = 1 ; j < 10 ; j++) { System.out.print ("*"); } Prints 9 stars ********* Gold Star Start j=1 j<10 * j++ End false true

11 Shape Formal: informal Rules Terminal: start, end Input/Output: IO keyboard input Process: calculations Display: output new Decision: Boolean expression There is only one start and one end. Arrows connect the pieces. Flow is up to down or left to right. Lines do not cross. The only shape with can have 2 lines come out of it is a diamond. No shape can have more than 2 lines come out of it.

12 I promise you: It s on the exam. System.out.println ("Welcome!\n"); char end = 'n'; while (end == 'n') { System.out.println ("\nthis is the song that never ends,"); System.out.println ("Yes it goes on and on, my friends!"); System.out.println ("Some people started singing it,"); System.out.println ("Not knowing what it was,"); System.out.println ("And they'll continue singing it FOREVER"); System.out.println ("Just because...\n"); } 1. Initialize the loop variable end = IO.inputChar ("End? (n/y) "); 2. Test the stopping condition System.out.println ("\nyou ruined the song! Good bye."); 3. Move towards the stopping condition 4. Steps to repeat

13 Big-Oh Name Algorithms O(1) Constant Time Swap, Reference an element O(log n) Logarithmic Time Binary search O(n) Linear Time Print, Sum, Max, Min, Average, Search, Bin Sort, Bubble (best case) O(n log n) Quicksort, Mergesort O(n 2 ) Quadratic Time Selection sort, Bubble sort O(n 3 ) Cubic Time O(2 n ) Exponential Time O(n!) Factorial Time O is order, N is the number of array elements. The entire notation is a mathematical expression for the number of operations required by the algorithm.

14 Good examples of diagram questions: Good examples of array questions: Complex arrays questions:

15 Trade-offs 1. Salad-Doughnut 2. Bin Sort 3. Bubble Sort 4. Selection Sort 5. PDLC 6. Backups 7. Housekeeping

16 Why useful? 1. Binary 2. Hexadecimal 3. ASCII 4. Variables 5. Types 6. Ifs 7. Boolean Expressions 8. Housekeeping 9. Backups 10. Flowcharts 11. Screen Flow Diagrams 12. Parameters 13. Return Types 14. Methods 15. Loops 16. Progress to Stopping 17. Stopping Variable 18. PDLC

17 Why useful? 19. Johnson 20. Structure Charts 21. User Centric Design 22. Analysis 23. Design 24. Testing 25. Algorithms 26. Sorting 27. Arrays 28. Big Oh Notation 29. Array Memory Diagrams 30. Bentley s example