Programming Basics

Programming Basics

1. Data Types

   • Programming languages have five main data types
     • Integer, Real, Boolean, Character, String
       • Whole numbers only (integer)
         • Real (Numbers that have a decimal part)
           • Boolean (Can only take one of two values, usually TRUE or FALSE)
             • Character (A single letter)
               • String ( Used to represent text, it is a collection of characters
   • Each data type is allocated to a different type of memory.
   • Using the correct data types makes code more memory efficient, robust and predictable
   • Languages have functions that let you manually convert between data types, this is known as casting
     • Casting is used to change the data type
     • int(), float(), bool(), str()

2. Strings

   • Strings are a data type made up of characters
     • Characters are alphanumeric (letters, numbers, spaces, symbols, etc.)
   • Strings are usually written inside double quotation marks.
     • Sometimes single quotes are used.
   • Strings can be joined together to form new strings, this is called concatenation.
     • Often done using the + operator
   • Programs let you manipulate strings in a variety of ways.
     • String manipulation functions:
       • x.upper
         • x.lower
           • x.length
             • x[i]
               • x.subString(a, b)
                 • Extracts a string starting at position A with length B from string x.
               • Extracts all the character in position i in string x
             • Returns the number of characters in string x
           • Changes all characters in string x to lower case
         • Changes all characters in string x to upper case