PROGRAMMING In

Objectives  We’re learning to develop basic code with the use of the correct syntax and variables. Outcomes  Explain what syntax is and why it’s required.  Explain the use of variables.

OBJECTIVES  Learn about python as a programming language  Learn about expressions & variables and their use  Create several successful programs O UTCOMES  All-State what a programming language is and what a program is. Get half marks on the test (7/15)  Most- Have used variables and with help get 75% on the test (12/15)  Some- Written their own programs and independently got maximum marks on the test.

STARTER Using the internet…Find …  what does “case sensitive” mean  what a programming language is..  3 benefits of Python

PYTHON  Python is a programming language  A set of words and rules for instructing a computer to perform specific tasks.computer  The term programming language usually refers to high-level languages, such as BASIC, C, C++, Python etchigh-level languagesBASICCC++  Each Programming language has a set of keywords and a special syntax for writing program instructions.Programming languagekeywordssyntaxprograminstructions

Learning to program is going to be fun – so lets keep it simple. org 100h main proc mov ah,9 ; mov dx,offset hello_message int 21h : retn hello_message db 'Hello, world!$' main endp end main print ("Hello, World!“) #include int main() { std::cout << "Hello World!" << std::endl; return 0; } C++ Assembler python WHY PYTHON

WHAT IS A PROGRAM  Programming is not telling the computer what you want to do….it is telling it EXACTLY HOW to do it (remember the student robot?!!)  A program is a sequence of instructions that specifies how to perform a computation.  The computation might be something mathematical, such as solving a system of equations  It can also be a symbolic computation, such as searching and replacing text in a document or moving a graphic icon (sprite) on a game.  You can think of a program like a recipe.  It contains a list of ingredients called “Variables”.  You can store many different types of information in a variable such as:  Data  Text  Images  A variable on it’s own is like a bucket….  You can get constant variables though…

TRADITION  It is tradition that the first program everyone creates is to say Hello world”.  From the start menu – all programs / python 3.4 / IDLE  MAKE SURE YOU ARE IN THE PYTHON SHELL  Enter the following and press enter print (“Hello, World”) This one If you see this window on top – look for the python shell window.

EXPRESSIONS – LOOK AT THE EXPRESSIONS BELOW. WHAT ANSWER DO YOU THINK THEY WILL RETURN? Now try typing these expression in idle, pressing return after each one print ( ) print (8*6) print (10-5+6) print ( 2 + 2)

EXPRESSIONS You have been using expressions 2 values and an operator Even the follows this rule Operators, you already know. Perhaps the multiplication is written differently as a * (on the number pad) At the moment python is acting like a calculator. 2+2 addition 2-2 subtraction 2*2 multiplication 2/2 division

SYNTAX In computer science, the syntax of a programming language is the set of rules that define the combinations of symbols that are considered to be correctly structured programs in that language.computer scienceprogramming languageprograms Aka syntax means that special key words and characters combine to result in a program.

SYNTAX  The syntax of a programming language is the set of rules that control if a program is correct.programming language  You tried print (“Hello, World”) and it worked – a correct program.  Try these print hello print (hello) PRINT(“hello”) print (a + b) print (5 + 6 / 7 +)  Syntax is CRITICAL in programming. A computer cannot take an educated guess at your instructions.  Computers just follow exactly what you tell them to do.

SYNTAX ERRORS Extension: - Now type out: print (hello world) What happens? SYNTAX ERROR Like with English, programming languages have their own check similar to a grammar check. When you run code it checks to see whether it is in the form for the computer to compute. If you do not do this the computer throws out an error like above.

VARIABLES Variables are like a bucket, they’re used to store a number, data, text or image. You can empty it or refill it as many times as you like. When we use variable in our code the computer uses the value in the variable. To store the value 15 in the variable and display it spam = 15 print (spam) Try it. Now try these spam = spam + 12 print (spam) spam = spam + spam print (spam) spam = spam * spam print (spam)

VARIABLES This time we have 2 variables eggs and fizz You can assign them by eggs = 15 fizz = 10 What be the output of the following, go on try it. print( eggs ) print( eggs + fizz ) spam = eggs + fizz print( spam ) eggs = fizz print( eggs ) print( EGGS ) >>>nothing 25 >>>nothing 10 Traceback (most recent call last): File " ", line 1, in EGGS NameError: name 'EGGS' is not defined In python eggs is not the same as EGGS. Python is case sensitive which means YOU MUST BE CAREFUL

COMBINE VARIABLES  You can do the same with numbers, for example:  Using number3 you can combine your sentence with the text you stored in your variable. You could do the same with names or other values. Notice the Comma separating it.

Show a syntax error and annotate it to explain it. Show how to print text or numbers. Show how to carry out calculations with numbers. Show use of variables through either calculation or text. See if you can make a sentence with the use of two variables.

COMPLETE SELF ASSESSMENT QUIZ Complete Self Assessment quiz from lesson 1 folder you copied at the start of the lesson. And update your self-evaluation for this lesson.