Write a program to animate a circle bouncing around a window. The basic idea is to start

A simple decision can be implemented with an if statement.

In Python conditions, =1- is written as/=.

Strings are compared by lexicographic ordering.

A two-way decision is implemented using an if- el if statement.

The math . sqrt function cannot compute the square root of a negative number.

A single try statement can catch multiple kinds of errors.

Multi-way decisions must be handled by nesting multiple if- el se statements.

There is usually only one correct solution to a problem involving decision structures.

The condition x <= y <= z is allowed in Python.

Input validation means prompting a user when input is required.

A year is a leap year if it is divisible by 4, unless it is a century year that is not divisible by 400. (1800 and 1900 are not leap years while 1600 and 2000 are.) Write a program that calculates whether a year is a leap year.

Write a program that accepts a date in the form month! day /year and outputs whether or not the date is valid. For example 5/24/1962 is valid, but 9/31/2000 is not. (September has only 30 days.)

The days of the year are often numbered from 1 through 365 (or 366). This number can be computed in three steps using int arithmetic: (a) dayNum = 31(month - 1) +day (b) if the month is after February subtract (4(month) + 23)/ /10 (c) if it's a leap year and after February 29, add 1 Write a program that accepts a date as month/ day /year, verifies that it is a valid date (see previous problem), and then calculates the corresponding day number.

Do Programming Exercise 7 from Chapter 4, but add a decision to handle the case where the line does not intersect the circle.

Do Programming Exercise 8 from Chapter 4, but add a decision to prevent the program from dividing by zero if the line is vertical.

Archery Scorer. Write a program that draws an archery target (see Programming Exercise 2 from Chapter 4) and allows the user to click five times to represent arrows shot at the target. Using five-band scoring, a bulls-eye (yellow) is worth 9 points and each successive ring is worth 2 fewer points down to 1 for white. The program should output a score for each click and keep track of a running sum for the entire series.

Write a program to animate a circle bouncing around a window. The basic idea is to start the circle somewhere in the interior of the window. Use variables dx and dy (both initialized to 1) to control the movement of the circle. Use a large counted loop (say 10000 iterations), and each time through the loop move the circle using dx and dy . When the x-value of the center of the circle gets too high (it hits the edge), change dx to -1. When it gets too low, change dx back to 1. Use a similar approach for dy . Note: Your animation will probably run too fast. You can slow it down by using update from the graphics library with a rate parameters. For example, this loop will be limited to going around at a rate of 30 times per second: for i in range ( 10000) : 241 update (30) # pause so rate is not more than 30 times a second

Take a favorite programming problem from a previous chapter and add decisions and/ or exception handling as required to make it truly robust (will not crash on any inputs). Trade your program with a friend and have a contest to see who can ''break" the other's program.