Autumn Term 2 Mr Reid Flashcards
what is iterative testing?
testing the code as it’s created, altering as required
what are the three types of error?
logic,runtime,syntax
what do logic errors do?
programs operate incorrectly-not crash- so unintended results
what are runtime errors?
an error that causes the program to crash even if there’s nothing wrong with the code, only detected when the program is run, eg run out of memory, infinite recursion
what is casting?
change a var’s data type
what is initialising?
giving a var a value when you create it
what is assignment?
changing a var’s value
what is a transcription/transposition error?
errors in transferring data onto computer
how can data entry errors occur?
transcription/transposition
source doc errors
what is verification (not passwords)
checking data to make sure its been transferred correctly
list some verification methods
double entry like password entry
proofreading
what can incorrect data lead to?
loss of income, reputation; legal ramifications; incorrect processing
why is it important to check data?
so data is as accurate as possible
are strings primitive data types
yes
can verification detect source doc errors?
no
can validaiton detect source doc errors?
yes
how is validation different to verification?
process to make data is sensible and valid, can be done by computer on input. used to check data against rules. can find source doc errors
list 5 types of validation
length check: is the data the expected length?
range check: is the data a sensible amount?
lookup check: does the data exist somewhere else? eg. a title like mr, ms, prof, etc.
format check: eg is it dd/mm/yy
presence check: is it there?
list characteristics of a low level language (5)
machine code+assembly language
tricky to program as programmer must do the logic reasoning
v. fast
produces small, efficient programs
often used in integrated systems
list high level language characteristics
easier to understand/write
can make big, sophisticated programs more easily.
englishish words.
platform dependant
what are characteristics of assembly code?
low-level,uses mnemonics,has an opcode and operand,has a 1-1 relationship with binary
what do assemblers do?
translate assembly code into machine code, platform dependant
does assembly code have a 1:1 relationship with machine code
yes
what do you use to translate assembly code into machine code?
an assembler
what does the SQL command SELECT do?
chooses data
what does the SQL command FROM do?
determines the table to grab data from
what does the SQL command INSERT do?
places new data into the table
what does the SQL command UPDATE do?
changes existing data
what does the SQL command DROP do?
gets rid of existing data
what does the SQL command DELETE do?
gets rid of existing data
what does the SQL command WHERE do?
criteria to meet
what does the SQL command OR do?
widens search criteria
what does the SQL command AND do?
narrows search criteria
what does the SQL command LIKE do?
similar to this
what language translator is needed for the first generation?
no translator
what sort of relationship do low-level to high level languages have?
one to many- for every high level instruction there are many low level instructions
what is the easiest generation to code in?
3rd gen
which generation would create the fastest code?
1st generation
what is meant by source code?
the code written by the programmer
what is used to translate assembly code?
assemblers
which gen of a programming language uses machine code?
1st gen
what language translator is used at the end of development?
compiler
which language translator produces object code and an error report?
compiler
which language translator is used with the second gen?
assembler
which language translator is used with the 3rd gen?
compiler
which language does not convert source code into machine code?
interpreter
which translator stops when it encounters an error?
interpreter
what features can an IDE include?
pretty text, predictive text, debugging tools including variable inspection, break point, step through
what does IDE stand for?
Integrated Development Environment
how are interpreters different from compilers?
they translate line by line and stop when they reach an error. slower than compiled problems
what is the opcode?
the instruction, eg ADD, SUB
what is the operand?
the data/value being acted on by the operand
how does the computer know whether a number is an instruction or value?
whether it is LDA (ing) or STA (ing) the number first
what do LDA and STA stand for in LMC?
Load and Store
what do BRZ and BRA stand for in LMC?
Branch when Zero and Branch Always
