Programming Basics

Programming Basics

1. Data types

   • Programming languages store data as different types
   • Each data type is allocated a different amount of memory
   • Using the correct data types makes the code more memory efficient, robust and predictable
   • Casting is used to change the data type
     • Languages have functions that let you manually convert between data types. This can be done using the int(), float(), bool() and str() commands
       • Operators
         • Operators are special characters that perform certain functions
         • the arithmetic operators take two values and perform a math's function on them
         • Addition, Subtraction, Multiplication and Division operators do what you'd expect
         • The exponentiation operator is used to raise a number to a power
         • The DIV operator returns the whole number part of a division and the MOD operator gives the remainder
         • These operators work on integers and real data values or a combination of the two
         • Constants and Variables
           • Data values can be stored as constants or variables.
           • The name of a constant or variable is linked to a memory location that stores the data value. The size of the memory location depends on the data type
             • Strings
               • Strings are usually written in double quotation marks but sometimes single quotes are used
               • Strings can be joined together to form new strings, this is called concatenation it's often done using the + operator
                 • Program flow
               • Before getting started on string manipulation you should know that the characters in a string are usually numbered starting at 0
           • A constant is assigned a data value at design time that can't be changed. if you attempt to change the value of the constant in a program then the interpreter or compiler will return error
           • Variables on the other hand can change value which makes them far more useful than constants
           • Constants and variables often need to be declared at the start of the program before you use them
     • its important the the integer 1, the real 1.0 and the string "1" and "1.0" are all different
     • You can also find the ASCII number of characters and vice versa using ASC() and CHR() functions