Labs

1. Write a program with a method that calculates a power — a base number raised to the power of an exponent. The method should take two parameters: a double (the base) and an int (the exponent). The method should return a double: the base raised to the power of the exponent. In the main method, prompt the user to enter the base and the exponent; use the method to perform the calculation; then print the result returned by the method. (Do not use Math.pow(double, double) in your solution.)

(Solution: PowerMethod.java)

1. We will be writing several methods in one class.

2. Write a method named calculateTriangle to calculate the "n^th triangle" for a given n. The triangle of a number n is 1 + 2 + ... + n. For example, calculating the triangle of 5 is 1 + 2 + 3 + 4 + 5 and the result is 15. The method will take an integer and return an integer. (Do not use the formula n * (n + 1) / 2 in your solution.)

3. Write a method named getNumber that prompts the use to enter a number. It will take no parameters, but will prompt the user to enter a number. The method will return the integer the user entered.

4. Call getNumber and your calculateTriangle method from (1) in main. Print the returned number. Now test your program. The main method below may help with the organization of your class.

   public static void main(String[] args) {
     //Call the method to get user data
   
     //Use the data to get triangle
   
     //Output the triangle
   }
   

   (Solution: TriangleCalc.java)

5. Write another method named calculateTriangleString to return a String representing the addition for an n^th triangle. For example, for the input 5, the method would return 1 + 2 + 3 + 4 + 5. Call the method from main after you output the triangle of a number. Test your program.

   (Solution: TriangleCalcString.java)

6. We will write overloaded test methods in our class from (2) to test triangle calculation.

7. Write a method called testEquals, which returns a boolean. The method will have two int parameters. The first parameter is the expected value. The second is a test value. If the two values are equal, print Passed and return true. If they are not equal, print Failed: expected X but was Y (where X and Y are the actual values of the parameters) and return false.

8. Comment out all code in main. Call your calculateTriangle method in main, and use the returned value in a call to testEquals. Do this method call with several values, and make sure you do so with a value that would cause testEquals to fail.

   (Solution: TriangleCalcTest.java)

9. Write a testEquals method with two String parameters. Use it to test the output of your calculateTriangleString Remember to use .equals() when testing the equality of String data. (Solution: TriangleCalcStringTest.java)

10. Review all vocabulary words from this section.

---

Prev -- Up