This simple flowchart shows how a conditional statement is used to help someone decide whether to go golfing

Flowcharting can be beneficial to all types of people, not just programmers, because it helps clarify what actually happens or needs to happen in an event or process. You can also use flowcharts to train people (for example, to illustrate what to do in the event of a fire at your school). With a flowchart, it is easier for you to identify problem areas and opportunities for improvement. In fact, while flowcharts are not as frequently used in programming as they used to be, they are used to capture business process models and decision making.

When you start Python, a window appears with some introductory text about the version you are running. Also, a prompt appears, waiting for your command: >>>

You will type your code after the >>> prompt. As soon as you hit the Enter key, that code will be interpreted (converted into machine language and executed). The result (if any) will display on the next line.

The simplest instruction to enter in Python is specifying a value at the prompt, which then becomes the output. Type the following sequence:

• 
  5
  The number 5 becomes the output.
  
• 
  5+2
  Python adds the two numbers, and the output is the number 7.
  
• 
  5*2
  Python multiplies the two numbers, and the output is the number 10.
  
• 
  5+2*3
  Notice that the computer obeys mathematical operator precedence rules by computing 2*3 first, before adding 5. The output is the number 11.
  

A string is a series of characters placed inside quotations marks. You can use either double or single quotes. Try typing "Hello there" . The output will be:

'Hello there'

Variables

Variables are names attached to memory locations, and they store information for us. For example, we can create a variable called age and another called name. We can then tell the computer to assign a value to the variable. To do this, we use an assignment statement. Type the following sequence:

• 
  age=15
  The number 15 is now stored as the value for the variable age. Notice that nothing is output in response to this instruction (unless you have a typo).
  
• 
  name="your name"
  Use your first and last name in place of your name. Don’t forget the quotation marks and the space between your names. Again, there is no output.
  
• 
  age
  This command does not output age but instead outputs the value stored in the variable age. The number 15 is the output.
  
• 
  name
  You should see your first and last name.
  

• 
  greeting="Hello "+name
  Don’t forget the space after hello but within the quote marks. The + is used to “add” strings together (known as string concatenation). In this case, we are creating a string of “hello ” (with a space) and your name combined together, placed into the variable greeting.
  

• 
  greeting
  You will see what is stored in the variable greeting. The two instructions should look something like the following.
  

Assignment statements are often used not just to store values but to perform computations. One type of computation is to change a value already stored in a variable. For this, we use a variation of the assignment statement where the variable appears on both the left and right side of the equal sign.

Let’s add 1 to age by using age=age+1. In a program, it means “take the value of age, add 1, and store the result in age.” Try the following sequence:

• 
  age=age+1
  
• 
  age
  The output should be the number 16.