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neurologyYou need to know

• A variable is a named memory location whose value can change, whereas a constant is a named value that should not change while a program runs.
• Input supplies data to a program, output communicates processed information, and assignment stores a value in a variable.
• Sequence executes instructions in order, selection chooses a path according to a condition, and iteration repeats instructions.
• A count-controlled loop repeats a known number of times, whereas a condition-controlled loop repeats while or until a Boolean condition is met.
• The arithmetic operators are addition `+`, subtraction `-`, multiplication `*`, division `/`, modulo `MOD`, integer quotient `DIV`, and exponentiation `^`.
• `DIV` returns the whole-number quotient of a division, while `MOD` returns the remainder.
• The comparison operators are equal to `==`, not equal to `!=`, less than `<`, less than or equal to `<=`, greater than `>`, and greater than or equal to `>=`; each produces a Boolean result.
• The Boolean operator AND is true only when both conditions are true, OR is true when at least one condition is true, and NOT reverses a Boolean value.
• An integer stores a whole number, while a real data type stores a number that may contain a fractional part.
• A Boolean stores either true or false, a character stores one symbol, and a string stores a sequence of characters.
• Casting temporarily converts data from one type to another, such as converting a numeric string into an integer so that arithmetic can be performed.
• Concatenation joins strings together, while slicing extracts a selected section of a string.
• File handling normally involves opening a file, reading data from it or writing data to it, and then closing it to release the resource and preserve changes.
• A record groups related fields about one entity, such as a student record containing a name, date of birth and candidate number.
• An array is a fixed-length, static structure whose elements are accessed using an index; a one-dimensional array forms a list and a two-dimensional array forms rows and columns.
• A two-dimensional array can emulate a database table in which each row represents a record and each column represents a field.
• A subprogram is a named, reusable section of code; a function returns a value, whereas a procedure performs a task without necessarily returning a value.
• A local variable or constant is accessible only within its subprogram, whereas a global variable or constant can be accessed from multiple parts of the program.
• Data, including arrays, can be passed into subprograms as parameters, and functions can return results, including arrays where the language supports this.
• An SQL query uses SELECT to identify the fields to retrieve, FROM to identify the table, and WHERE to filter records that meet a condition.

• Write programs that use variables, constants, input, output and assignment with meaningful identifiers and suitable values.
• Construct algorithms using sequence, selection, count-controlled loops and condition-controlled loops so that control flow matches the problem requirements.
• Form arithmetic, comparison and Boolean expressions using the correct operators and precedence to calculate values and test conditions.
• Choose suitable integer, real, Boolean, character and string data types for a scenario, and cast values when a different type is temporarily required.
• Manipulate strings by concatenating values and slicing strings at the required positions.
• Create, populate, traverse and update one-dimensional and two-dimensional arrays using valid indices and appropriate loops.
• Open, read, write and close files in the correct order, processing stored records accurately.
• Decompose a program into functions and procedures, passing required parameters and return values while using local and global data appropriately.
• Write SQL queries using SELECT, FROM and WHERE to retrieve specified fields and filter records by given criteria.
• Generate and use random numbers within an appropriate range, such as for simulations, games or random selections.