We’ve learned how to count up the player’s points but what happens if the player wins bonus points at the end of a round. How do we calculate them?
We can use expressions for this.
Expressions are programming statements that are evaluated and converted into a value. The expression below returns a value of 300 by using the ‘+’ operator to add numbers together:
100 + 200
Expressions can use variables. The expression below returns the value of the points variable and 100 added together:
points + 100
Assigning Variables Using Expressions
Now we can assign a new ‘bonus points’ variable that rewards the player for completing the round quicker:
bonus_points = 10000 / time_taken_seconds # Set bonus points to 1000 divided by the number of seconds it took to win the level
Keep in mind that some numbers are different from others. For example, some numbers are only whole numbers, others can have decimal points.
Most languages are smart enough to store the values after the decimal point when required. If we were writing a Python program to convert Fahrenheit temperatures to Celsius, we could use two variables:
fahrenheit = 55 celsius = (fahrenheit - 32) * 5 / 9 print(celsius) # prints out 12.777777777777779
So now we know how to calculate the points in the game using numeric variables.
That helps us write our game but we often need other types of variables in our other programs. We will discuss them next.
In this exercise, we’ve added operators that can modify our
goalPosition variables using mathematical operators such as:
moveDistance starts at 1, and we can find the goal position by reading the grid.
Use these operators to get Codey to their goal.
One option is to use
moveDistance. Another is to
divide the goal positions.
Add 5 to moveDistance Move Right Add 1 to moveDistance Move Down