Week 2 session exercises
1. Magic
Write a program that prompts the user for an integer and then performs the following operations with it:
- adds to it the next largest integer, i.e. an integer that is larger than it by one;
- adds 9 to the result;
- divides the result by 2;
- subtracts the original integer from the result.
Then the program outputs the number obtained.
Test your program with different numbers.
Do you notice anything special? How do you explain it?
2. Pizza price
Write a program that prompts the user for the diameter and price of the pizza. The diameter is in centimeters and the price is in euros. The program calculates the price of a square centimeter of the pizza in eurocents and prints the result.
What is the diameter of your pizza? 20 How many euros does it cost? 5 One square cm of your pizza costs 1.5915494309189533 cents.
Hint. See Java API for class Math.
3. Speeding fines
If the driver exceeds the maximum speed limit, then a cautionary fine is imposed. According to the Traffic Act, the size of the fine in euros is calculated by multiplying the number of km/h-s above the speed limit by 3 (see link). Maximum size of the cautionary fine is 190 euros.
Write a program that:
- prompts the user for name, speed limit and actual speed;
- computes the size of the fine, using the rules above;
- prints the name and the size of the fine on the screen.
Example
Enter name: Anver Enter speed limit (km/h): 60 Enter actual speed (km/h): 80 Anver, your fine for exceeding the speed limit is 60 euros.
Explanation: actual speed was 80 − 60 = 20 km/h above the speed limit. Therefore, the size of the fine is 3 · 20 = 60 euros.
Second example
Enter name: Sal-Saller Enter speed limit (km/h): 50 Enter actual speed (km/h): 172 Sal-Saller, your fine for exceeding the speed limit is 190 euros.
Explanation: the speed was 172 − 50 = 122 km/h above the speed limit. Preliminary calculation gives the size of the fine as 3 · 122 = 366 euros. Since this exceeds the maximum size of the fine, the fine will be 190 euros.
Hint: to take into account the maximum size of the fine, you can use the function Math.min. For example, if the variable res has a value larger than 190, then the value of Math.min(190, res) is 190.
4. Countries and currencies
To solve this task, you may want to look at the methods in the classes java.util.Locale and java.util.Currency.
a) Write a program that outputs the values of country, language and currency for the current instance of the Java Virtual Machine (i.e. you own computer).
Country: Eesti Language: eesti Currency: EUR
b) Write a program that for the given language name and outputs all countries that use that language and the currencies that these countries use.
Enter language: German Austria EUR Germany EUR Switzerland CHF Luxembourg EUR . . .
c) Write a program that for the given currency abbreviation finds all countries that use that currency.
Enter currency: ALL Albania
5. Opinion of Java
Create a text file and write what are your first impressions of Java. What are the largest differences compared to Python? What of the material covered so far should be reviewed or explained again?