St Brendan’s as computer Science Summer task Summer 2016 St Brendan’s Computer Science Summer task
User input using Scanner with BlueJ
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- 4 Pseudocode trace
| 3 User input using Scanner with BlueJ
Type this code carefully into BlueJ. Now run as a program in BlueJ and test with data.  
NOTE: / gives integer division eg 15 / 6 = 2 % gives the remainder eg 15 % 6 = 3
Note: it can be helpful in debugging a program to add a breakpoint and examine how your program behaves from that breakpoint line by line. For an example on adding a breakpoint see video: https://www.youtube.com/watch?v=Q625RZTc1Ho 4 Pseudocode trace Pseudocode is a way of describing an algorithm without using a specific programming language. A trace is a way of checking an algorithm by working through line by line of an algorithm and keeping track of each relevant value. In the A level course you will be expected to use both. Trace 1 The pseudocode below is traced for input value 5 and then for input value 8 Pseudocode Trace table for input value 5 input a if a MOD 2 is 1 output a else
output a – 1 end if
Trace table for input value 8
Where MOD means remainder. For example 13 MOD 5 is 3 because when 13 is divided by 5 the remainder is 3. Youtube recording for this example: www.youtube.com/watch?v=PSpm9d2kq_o The purpose of this pseudocode is: to output an odd number that is the same as the input number, if the input is odd, or one lower than the input number if the input is even. Trace 2
Consider the pseudocode in the box alongside: Note: The pseudocode contains a loop starting at line 6: ‘for i is 3 to n’ and ending at the line 11: ‘end for loop’. This means lines 7 to 10 are repeated (in the order: 7, 8, 9, 10, 7, 8, 9, 10 . . . etc.) This loop is controlled by stepper variable, i, which starts with a value of 3 and at the end of each iteration is increased by one until in the final iteration it reaches a value of n. Suppose the algorithm is traced with variable n having a value read in of 10. We produce a trace by considering and tracking the values of each variable: n, i, sum, v1, v2 and what is output as we work through the pseudocode one line at a time (repeating lines 7 to 10 for each value of i).
Notice:
the table shows n stays as 10 all the way through i has values 1,2, . . . , 10 v1 and v2 start with value 1 when i is 3, the value of sum is set to 2, v1 changes to 2 and 2 is printed out etc HELP:
See video on how to fill in this trace table: www.youtube.com/watch?v=ycdcDYl7yd4 When tracing an algorithm make sure you work through carefully one line at a time and do not worry about the purpose of the algorithm until you have finished. The purpose of this algorithm is to print out the first n values of the Fibonacci sequence. Research the Fibonacci sequence and check if the algorithm works for other values of n. I think this algorithm should work fine for most whole number values of n. But what about values less than 2 (n= 1 or 0 or a negative). We can rewrite the algorithm so that it will better cope with n being 1 or less by printing out the correct number or giving an error message. Java Work – do this before attempting Java exercises (or after you get stuck!) Make sure you have completed sections 1-4 of this booklet. Go to chortle site http://chortle.ccsu.edu/CS151/cs151java.html or use mirror site http://programmedlessons.org/java5/index.html. Go through chapters 8 – 11 and do as many exercises and quizzes as you need. Set aside at least six hours to work through these chapters and more if you do more than a few of the exercises. After chapters 8 – 9c attempt question 1 below (filling in answers 01 to 03). After chapters 10 – 11 attempt question 2, 3 and 4 below (filling in answers 04 to 11). Directory: upload upload -> 587 Return function, r i(X) r i(0) r i(1) r i(2) r i(3) 1 0 2 4 6 Thermal Station, I 2 0 1 5 6 3 0 3 5 6 10 upload -> Department of science and humanities department of mathematics part-a questions and answers upload -> The Case Against the nypd’s Quota-Driven ‘Broken Windows’ Policing What Is It? upload -> For want of a nail upload -> Traditional British values upload -> Tv shows, Made for tv movies, Mini Series & Internet Programs Shot at Paramount Ranch upload -> Ownership Models There are two different types of ownership models upload -> Police Militarization upload -> City of rising star regular meting thursday, july 14, 2016 upload -> Township of winfield Download 1.82 Mb. Share with your friends:
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