Except where otherwise noted, the contents of this document are Copyright 2013 Stuart Reges and Marty Stepp.
lab document created by Marty Stepp, Stuart Reges and Whitaker Brand
Goals for this problem set:
return
values to send data between methodsA return value is when a method sends a value back to the code that called it.
public static type name(parameters) { // declare
...
return expression;
}
variableName = methodName(parameters); // call
Example:
public static double fToC(double tempF) { return (tempF  32) * 5.0 / 9.0; } ... double bodyTemp = fToC(98.6); // bodyTemp stores 37.0 double freezing = fToC(32); // freezing stores 0.0
Method  Description  Example 

Math.abs

absolute value 
Math.abs(308) returns 308

Math.ceil

ceiling (rounds upward) 
Math.ceil(2.13) returns 3.0

Math.floor

floor (rounds downward) 
Math.floor(2.93) returns 2.0

Math.max

max of two values 
Math.max(45, 207) returns 207

Math.min

min of two values 
Math.min(3.8, 2.75) returns 2.75

Math.pow

power 
Math.pow(3, 4) returns 81.0

Math.round

round to nearest integer 
Math.round(2.718) returns 3

Math.sqrt

square root 
Math.sqrt(81) returns 9.0

Write the results of each expression.
Use the proper type (such as .0
for a double
).
Note that a variable's value changes only if you reassign it using the =
operator. Discuss any errors you make with your neighbor.
double grade = 2.7; Math.round(grade); // grade = 2.7 grade = Math.round(grade); // grade = 3.0 double min = Math.min(grade, Math.floor(2.9)); // min = 2.0 double x = Math.pow(2, 4); // x = 16.0 x = Math.sqrt(64); // x = 8.0 int count = 25; Math.sqrt(count); // count = 25 count = (int) Math.sqrt(count); // count = 5 int a = Math.abs(Math.min(1, 3)); // a = 3
Consider the following method for converting milliseconds into days:
// converts milliseconds to days public static double toDays(double millis) { return millis / 1000.0 / 60.0 / 60.0 / 24.0; }
Write a similar method named area
that takes as a parameter the radius of a circle and that returns the area of the circle.
For example, the call area(2.0)
should return 12.566370614359172
.
Recall that area can be computed as π times the radius squared and that Java has a constant called Math.PI
.
Write a method named pay
that accepts two parameters: a real number for a TA's salary, and an integer for the number of hours the TA worked this week.
The method should return how much money to pay the TA.
For example, the call pay(5.50, 6)
should return 33.0
.
The TA should receive "overtime" pay of 1 ½ normal salary for any hours above 8.
For example, the call pay(4.00, 11)
should return (4.00 * 8) + (6.00 * 3) or 50.0
.