Now that we’ve learned what variables are, let’s learn to create and use them.
When creating variables, some computer languages require us to declare them, others create them automatically. For example:
- Java requires variables to be declared.
- Python doesn’t require variables to be declared.
When we declare a variable, we specify a variable name, additional information like the data type, and sometimes the initial value.
In Java a variable declaration looks like this:
In Python, we can create a ‘points’ variable and assign it a value of twenty like this:
As the game is played and the user wins points, we can update the points, reassigning the variable’s value:
And if we want to print out the points at the end of the game, we can retrieve the variable’s value using its name:
This is perfect for counting and printing the points. However, variables are often used to store the values of complex calculations and in the next exercise we will learn about using expressions for calculations!
Instructions
For this exercise, we don’t have enough blocks to move Codey to the goal with only the move commands! Assign variables such as goalPositionX or moveDistance values by combining the teal number block with the set command. Select different variables using the dropdown menu on the set command. Play with the following variables:
goalPositionXto move the horizontal position of the goal (See the starting value on the grid)goalPositionYto move the vertical position of the goalmoveDistanceto change how far Codey goes in the nextmovecommand (Starts at 1)
There are many ways to solve this puzzle; try exploring!
Hint
- Try moving the goal position closer to Codey
- Try increasing the
moveDistanceto make Codey go farther with each move command
Solution
One possible solution