BTEC Computing Unit 1 Learning Aim A and B COMPUTER SCIENCE ALL SOLUTION LATEST EDITION GUARANTEED GRADE A+

What is computational thinking? It enables you to analyse a problem, break it down into smaller parts and identify a strategy to solve the problem. Decomposition the act of breaking down (decomposing) a complicated task into a set of more easily identifiable subproblems. 3 steps of decomposition break down the problem into subproblems break down the problem into a series of steps communication - you need to be able to explain the key features of a problem to others. pattern recognition identifying similar subproblems and then solving them using the same method. Benefits of pattern recognition There may be multiple similar subproblems in a problem, if a single method can solve them all, it is more efficient. If a different but similar problem occurs, we can reuse a lot of the solution, saving time. Algorithm A step-by-step procedure for solving a problem, especially by a computer. Algorithm design can be broken down into 5 distinct steps: - Understanding the problem - do you know exactly what you are being asked to do - Identify the inputs - what data needs to go into your program - Identify the processes - are there any calculations or computational operations happening? - Identify the data storage - do you need a database or a text file? - Identify the outputs - what data is coming out of your program? code libraries Programmers will keep copies of program segments that can be re-used with different applications to solve a similar problems. Benefits of using code libraries Debugging time can be reduced as these program segments will have been tested and signed off as fit for purpose. Abstraction removing unnecessary information from a problem, so that finding a is solution is made easier Variables Values in a problem or system that may change Usually input by the user or may result from a calculation. Constants Values in a problem or system that remain fixed while the code runs (can not be changed) Key Processes (problem solving) Processes that are essential to the understanding of a problem or how a system works. Repeated Processes Processes that occur multiple times within a problem Inputs Values read or entered into a system Outputs Information presented to the user Flowchart A diagram that shows different paths a program will take depending on what data is inputted. Terminal (flowchart) This is what is used to either start or end a flowchart, larger flowcharts can use multiple end terminals. This is represented by an oval shape Input/output (flowchart) We use this symbol to show some form of input or output. it would be used to represent the output PRINT, or for user input. This represented in the shape of a parallelogram. Process (flowchart) Rectangles are used for processes and calculations For example, x = x + 4 Decision (flowchart) This symbol is used for decisions where we ask questions that change the path of a program. We tend to use Yes/No questions for decisions in flowcharts. For example, Is x 5? Connector (Flowchart) Flowchart component that shows which step of the algorithm leads to which other step; represented by a line Pseudocode Simplified representation of a programming language used to help plan how an algorithm should be programmed What is Pseudocode made up of? It is broken up into Operations, Decisions and Repetitions. Name all the Operation terms (Pseudocode) - BEGIN - END - INPUT - OUTPUT - PRINT - READ - WRITE Name all the Decisions terms (Pseudocode) - IF - THEN - ELSE - ELSE IF - WHEN Name all the Repetition terms (Pseudocode) - FOR - REPEAT UNTIL - WHILE - WHILE NOT Why would you use Pseudocode? It can be used to work out if the final program is going to do what the user wants it to do. Benefits of Pseudocode - can help programmers suggest improvements to how the code should work. - help improve the efficiency of code by reducing the number of lines needed or the number of variables used. - It can help programmers spot errors before they appear in the final program. resolving these problems before we even start actual development can help save time and money in the long run. Trace tables a technique used to analyse the output of an algorithm on paper Input (Pseudocode) Pseudo command that gets data from the user OUTPUT (Pseudocode) Pseudocode command that displays data to the user FOR (Pseudocode) Pseudocode command that repeats a block of code, looping through a specified series of values ELSE (Pseudocode) Pseudocode command that states a block of code should run if all previous conditions were not met IF (Pseudocode) Pseudocode command that checks a condition and if the condition is true, runs a block of code ELSE IF (Pseudocode) A conditional statement performed after an IF statement that, if true, runs a specific block of code WHILE (Pseudocode) Pseudocode command that repeats a block of code for as long as a specific condition is true WHILE NOT (Pseudocode) Pseudocode command that repeats a block for code for as long as the specified conditions are false REPEAT UNTILL (Pseudocode) Pseudocode command that repeats a block of code until a certain condition is met CONTINUED..