Homework 2 - I/O and Methods
Overview
The purpose of this first homework is to give you practice with handling user input and output, as well as writing your own methods.
This homework has many problems, but they are all relatively short. In the future, homeworks will have fewer, more complex problems.
Questions 1-8 are coding questions.
Question 9 is a written response question.
Make sure to follow the collaboration policy for all homework.
As before, the name after the question number should be what your program is called.
Note that when you take user input for turning in your homework, you should not have a text prompt to do so. That is, the only thing that the program should print is the requested output. Each homework question below has an example of what should print based on a given input. The > indicates the input.
Assessment
For Proficiency credit, your submissions for 1-8 must pass all test cases in Gradescope. Your submission for 9 must describe an accurate algorithm.
For Mastery credit, your submission must pass all test cases, and also have:
- Useful, informative variable names
- Clear and consistent spacing/linebreaks
Your written submission must describe an accurate algorithm, and also must:
- Be consistent in its language (e.g., not switching between pseudocode/Java/English)
- Include an example
Questions
Q1: PrintOne.java
Write a program which contains a method called echo() that takes a single string as an argument and directly prints the string. Call this method in main.
Example:
> Hello!
Hello!
Q2: PrintTwo.java
Write a program which contains a method called heard() that takes a single string as an argument and returns that same string. Call this method in main, but do not print the result.
Example:
> Hello!
Note that this should print nothing.
Q3: ConvertDouble.java
Write a program which contains a method called intToDouble() that takes an integer as an argument and returns the integer as a double with a single 0 after the decimal. Print the integer and double with -> between them.
Example:
> 7
7 -> 7.0
Q4: ConvertInt.java
Write a program which contains a method called doubleToInt() that takes a double as an argument and returns the double as an integer. Print the double and integer with -> between them.
Example:
> 8.4
8.4 -> 8
Q5: AreaVolume.java
Write a program which calculates both the area of a circl eand volume of a sphere with a given radius.
The formula for area of a circle is:
\[A = \pi r^2\]The formula for volume of a sphere is:
\[V = \frac{4}{3} \pi r^3\]It should then print them rounded to 3 decimal places, labeled as Area: and Vol:.
Use at least two methods other than main. One of the methods should call the other.
Example:
> 4
Area: 50.265
Vol: 268.083
Q6: CourseName.java
Rewrite your CourseName.java program from week 1 so that instead of having a set course name, the program takes a course name as input.
Example:
> CMSC510
This course is called CMSC510.
Q7: Eggs.java
Rewrite your Eggs.java program from week 1 so that:
- Instead of having a set number of eggs, the program takes an integer as input, and
- The conversion from number of eggs to number of dozens happens inside its own method, which takes one argument (the number of eggs) and returns (not prints) the number of dozens.
Example:
> 30
You have 30 eggs (2.5 dozen).
Q8: Convert.java
Rewrite your Convert.java program from week 1 so that:
- Instead of having a set number of glorps, the program takes a double as an input
- Instead of having a set conversion rate, the program takes a double as an input (to account for possibly varying conversion rates)
- The conversion happens inside its own method, which takes two arguments (the number of glorps and the conversion rate, and returns (not directly prints) the number of murps.
Example:
> 25
> 0.5
12 murps
Q9: Free Response Question
Write out an algorithm for converting a number from binary to decimal. This algorithm does not have to be in Java or in pseudocode; it can be in plain english. It should have clear steps to follow and should work for any positive binary number.