Chapter 1: The Way Of The Program

Chapter 1: The Way Of The Program

1. 1.1 Programming Language

   • Computers can only run programs that have been written in 'low-level languages.' If written in 'high-level languages', it has to be processed.
     • Advantages Of High Level Language
       • It is easier to program in a high-level language.
       • High-level language take less time to write.
     • Advantages Of Low Level Language
       • Low level language does not have to be processed before it is ran through a machine
   • What Is A Complier And An Interpreter? They both read the program and translates it completely before the program starts running.
     • Python programming is execucted through an interpreter

2. 1.2 What Is A Program?

   • A program is a sequence of instructions that specifies how to perform an action.
     • The action might be mathematical, such as solving equations but it can also be a symbolic action, such as searching and replacing text in a document.
     • Here are a few examples of basic instructions used in programming
       • Input: Get data from the keyboard, a file, or some other device.
       • Output: Display data on the screen or send data to a file or other device.
       • Math: Perform basic mathematical operations like addition and multiplication.

3. 1.3 What Is Debugging?

   • Here are a few types of errors that would need to be debugged.
     • Syntax errors: Python can only execute a program if the syntax is correct.
     • Runtime errors: they are called this because the error does not appear until after the program has started running.
     • Semantic errors: If there is an error, the computer will not generate any error messages, but it will not do the right action.

4. 1.4 Formal and Natural Lanuages

   • Natural languages are the languages people speak, such as English, Spanish, and French and they have evolved naturally.
   • Formal languages are languages that are used by people for particular applications. For example, the language that mathematicians use is a formal language that is particularly good at showing relationships in numbers and symbols.
   • Formal languages tend to have strict rules. For example, 3 + 3 = 6 is correct mathematical statement, but 3 + = 3 $ 6 is not.

5. 1.5 The First Program

   • Normally, the first program you write in a new language is called “Hello, World!” because all it does is display the words “Hello, World!”. In Python, it looks like this:
     • print 'Hello, World!'
       • It will look like this when the program has ran.
         • Hello World
   • Even though in the other Python applications, the first instruction would be written as:- print 'Hello, World!', in Python 3, the instruction for printing is slightly different: print ('Hello, World!')
     • But, it still prints the text how it did before.

6. 1.6 Debugging

   • Debugging be anything so simple. It could be that you spelt the instruction wrong.
     • For example: prnt 'Hello, World!'
   • Or it could be that you've missed out some very important punctuation!
     • For example: print 'Hello, World!