Chapter 1 – Programming Basics

Chapter 1 – Programming Basics

1. Input/output Statements

   • Input statement allows the user to enter data
     • Eg. USERINPUT
   • Output statement allows the program to display/print data
     • Eg. OUTPUT

2. Comments

   • Used to show what each bit of the code does, documenting who made it, the time and date of creation/last revision etc.
   • Shown using a #

3. Data Types

   • Integer - a whole number Eg. -25, 0, 3, 54842
   • Boolean - a variable that can only be TRUE or FALSE
   • Character = a letter, number or special character that is represented in ASCII. Eg. A, ?, 4
   • String = anything enclosed in speech marks. Eg. "Dan"
   • Real/Float - a number with a fractional part Eg. -13.5, 0.0, 3.142

4. Common Arithmetic Operators

   • -,+,* and / are common arithmetic operators
     • Used in most programming languages and pseudocode

5. Exponentiation

   • To find a square of a number (eg. 25) you need to use exponentiation
     • In pseudocode written as x ← y**n

6. Finding a Remainder

   • Found using the mod function – written % in python
     • Returns just the remainder
     • Eg. 20%3 = 2 i.e. the remainder is 2.

7. Integer Division

   • Found using the div function – written // in python
     • Eg. 20//3 = 6

8. String Handling Functions

   • Concatenating Strings
     • To concatenate means to join two strings together
       • Use the + operater to do this
       • Eg. "Johnny" + "Bates" = "JohnnyBates"
   • String Conversion Operations
     • int("1")|Converts a character to an integer. Eg. "1" would become 1
     • float("123.456")|Converts a string to a real number. Eg. "123.456" would become 123.456
     • str(123.456)|Converts a real number to a string. Eg. 123.456 would become "123.456"
     • date(year,month,day)|Returns a number that you can use to calculate with. i.e turn into a string.
     • str(123)|Converts a integer to a string. Eg. 123 would become "123"
   • Constants
     • Constants are values that never change throughout the program
       • Makes is so the programmer cannot accidentally change the data
   • Variables
     • Variables are identifiers (ie. Names) given to data that can change throughout the program
       • Names should be meaningful to the data contained
         • Easier for other programmers and you to follow and make changes
   • Some programming laguages require that you declare the varables and constants you want to use in your program before you can use them in the program.