Problem Solving

• Algorithm


  a methodical, logical rule or procedure that guarantees solving a particular problems.
• Pseudocode


  a high-level description of the actions of a program or algorithm, using a mixture of English and informal programming language syntax
• data type


  All values in a programming language have a "type" - such as a Number, Boolean, or String - that dictates how the computer will interpret it.
• Integer


  All whole numbers (both positive and negative) and zero.
• Real/Floating Point


  A number with a fractional part such as -13.125
• Boolean


  A single value of either TRUE or FALSE
• Character


  A letter,number or symbol represented in a character set table such as ASCII
• string


  a sequence of characters usually enclosed in quotation marks
• Arithmetic Operators


  The symbols +, -,, /, %, and* used to denote addition, subtraction (or negation), multiplication, division, percentage, and exponentiation in a formula.
• DIV


  function used in programming to find the integer result of a division.
• MOD


  function used in programming to find the remainder of a division.
• len(string)


  returns the number of characters in a string
• string.find(substring)


  Returns index of first location if found; returns -1 if not found
• ord("a")


  Returns the integer value of a character from the ASCII table.
• chr(97)


  Returns the character represented by the integer from the ASCII table.
• Concatenation


  A process that joins two strings together using the + operator. Eg "string" + "string" = "stringstring".
• Constant


  A value that does not change during program execution.
• Variable


  A value that can change during program execution.
• Selection


  A generic term for a type of programming construct (usually an if-statement) that uses a Boolean condition to determine, or select, whether or not to run a certain block of code.
• Sequence


  Two or more programming statements that follow each other in order.
• Iteration


  A generic term for a type of programming construct (usually a for or while statement) that uses Boolean conditions or counters to determine how many times a code block is repeated.
• Assignment


  Assigning a value to a variable using the = operator.
• Relational Operators


  Used to compare two values. Operators include ==,<,>,<=,>=,!=
• IF...THEN...ELSE statement


  IF (expression1) THEN

  (do these statements)

  ENDIF
• SWITCH-CASE statement


  some programming languages support the use of switch/case statements. It is an alternative to nested IF statements.

  SWITCH (choice):

  CASE1 : print("You have chosen option 1)

  (more ststements)

  CASE 2: print("You have chosen option 2)

  (more ststements)

  CASE 3: print("You have chosen option 3)

  (more ststements)

  ENDSWITCH
• Boolean Operators


  AND, OR, NOT, XOR
• While loop


  a programming construct used to repeat a set of commands while a boolean condition is true.
• For loop


  Loops that have a predetermined start, stop, and increment (step interval).
• repeat until loop


  A type of loop in some languages that is a post test loop, similar in structure to a do while loop, but terminates when the check condition is true, unlike the do while which terminates when the check is false.
• do-while loop


  repeatedly executes a block of statements until a specified Boolean expression evaluates to false.
• WHILE statement


  WHILE(condition):

  (statements)

  ENDWHILE
• FOR statement


  FOR (counter(optional start, stop step)):

  (statements)

  NEXT counter
• REPEAT...UNTIL statement


  REPEAT

  (statements)

  UNTIL (condition)
• Nested loops


  a loop that is contained within another loop
• Subroutine


  a named block of code which performs a specific task within a program.
• Function


  A function is a subroutine that always returns 1 value.
• Procedure


  A procedure is a subroutine that returns 0 or many values.
• Function structure


  DEF functionname():

  (statements)

  return value

  END FUNCTION

  
  

  DEF Main():

  value = functionname()

  END MAIN
• Procedure structure


  DEF procedurename():

  (statements)

  END PROCEDURE

  
  

  DEF Main():

  procedurename()

  END MAIN
• Passing by value


  refers to the process of passing a copy of a variable's value to a subroutine.