module 2: algorithms and programming computing notes by niq

󾠯 module 2: algorithms and programming tbh not much but: types of validation checks: 1. length check 2. range check 3. presence check 4. format check 5. existence check 6. calculation of check digit types of errors: 1. syntax error 2. logic error 3. run-time error trace tables types of conditions: 1. normal conditions 2. boundary conditions 3. error conditions algorithm design flowchart symbols: 1. terminator 2. data 3. decision 4. process module 2: algorithms and programming 1

types of validation checks: 1. length check checks if input is the correct length (eg 5 characters long) 2. range check checks if input is within the specified range (eg 10 to 20 inclusive) 3. presence check checks if input exists (eg valid input = “5”, invalid = “” or “ “) 4. format check checks if input is in correct format (eg 5 characters long and 2 digit number at the end) 5. existence check checks if input lies in a database (eg if input is in the list) 6. calculation of check digit types of errors: 1. syntax error caused by incorrect source code that violate rules of language, preventing the code from running (eg: if type = “5”: ) 2. logic error caused by program not behaving as expected, with the actual output differing from the expected output (eg: multiplying instead of dividing) 3. run-time error 2.6 Software Engineering module 2: algorithms and programming 2

occurs while program is running (eg dividing a string midway through the program) trace tables one step is one row how it shld look like: types of conditions: num = input("enter number: ") if num >=1 and num<=20: print("within range") 1. normal conditions input data is expected input during normal use of program module 2: algorithms and programming 3

eg. if num = 5, output will return “within range” 2. boundary conditions input is at limit of what program is designed for, or where special handling of input is required eg. if num = 1, output will return “within range” 3. error conditions input data that should be rejected by program via input validation eg. if num = 0, error algorithm design flowchart symbols: 1. terminator “pill” shape represents the beginning or end of a set of steps; usually labelled with either START or END/STOP 2. data parallelogram shape represents either receiving input data from outside the algorithm (labelled with INPUT) or producing output from within the algorithm (usually labelled START/END/STOP labelled inside module 2: algorithms and programming 4

with OUTPUT 3. decision diamond shape represents a step involving a question arrows outgoing usually are labelled “Yes” and “No”; only one of these outgoing arrows should be followed when performing the algorithm 4. process rectangle shape represents the beginning or end of a set of steps usually involves changing the value of a variable or performing more complex actions INPUT number/OUTPUT number labelled inside number > 0? labelled inside module 2: algorithms and programming 5

2.6: Software Engineering Understand and describe the stages in developing a program: gather requirements, design solutions, write code, test and refine code, deploy code. Recognise that the sequence of software development stages may not be linear and the use of iterative development may sometimes be more appropriate. count += 1 labelled inside module 2: algorithms and programming 6