Data
Working with data types
Math class
The Math class
java.lang.Math
Common static methods of the Math class
| Method | Returns |
|---|---|
| round(float or double) | The closest long value to a double value or the closest int value to a float value. The result has no decimal places. |
| pow(number, power) | A double value of a double argument (number) that is raised to the power of another double argument (power). |
| sqrt(number) | A double value that's the square root of the double argument. |
| max(a, b) | The greater of two float, double, int, or long arguments. |
| min(a, b) | The lesser of two float, double, int, or long arguments. |
| random() | A random double value greater than or equal to 0.0 and less than 1.0. |
Math class examples
The round method
long result = Math.round(1.667); // result is 2
int result = Math.round(1.49F); // result is 1The pow method
double result = Math.pow(2, 2); // result is 4.0 (2*2)
double result = Math.pow(2, 3); // result is 8.0 (2*2*2)
double result = Math.pow(5, 2); // result is 25.0 (5 squared)
int result = (int) Math.pow(5, 2); // result is 25 (5 squared)The sqrt method
double result = Math.sqrt(20.25); // result is 4.5The max and min methods
int x = 67;
int y = 23;
int max = Math.max(x, y); // max is 67
int min = Math.min(x, y); // min is 23The random method
double x = Math.random() * 100; // result is a value >= 0.0 and < 100.0
long result = (long) x; // converts the result from double to long
Code that generates a random number.
public class SomeRandomNumbers
{
public static void main (String[] args)
{
// random number 0.0 up to but not including 1.0
double ran = Math.random();
System.out.println(ran);
// between 1 and 10
int ran1 = 1 + (int) (Math.random()*10);
System.out.println(ran1);
// between 1 and 13
int ranCard = ((int) (Math.random()*100)%13+1);
System.out.println(ranCard);
}
}
The console after the program finishes
