All Flashcards
What is a static method?
A method that belongs to the class itself rather than to an instance of the class. It can be called directly using the class name.
What is the absolute value of a number?
The distance of a number from zero, always non-negative.
What does inclusive mean in the context of ranges?
Including the specified endpoint in the range.
What does exclusive mean in the context of ranges?
Not including the specified endpoint in the range.
What is the purpose of the Math class in Java?
To provide static methods for performing common mathematical operations.
What is the return type of Math.random()?
double
What is the return type of Math.abs()?
The same type as the input argument.
What is the return type of Math.pow()?
double
What is the return type of Math.sqrt()?
double
What is the purpose of casting to int when using Math.random()?
To convert the double value returned by Math.random() to an integer, effectively truncating the decimal part.
What does the following code output?
java
System.out.println(Math.abs(-10 + 3));
7
What does the following code output?
java
System.out.println(Math.pow(4, 0.5));
2.0
What does the following code output?
java
System.out.println((int)(Math.random() * 6) + 1);
A random integer between 1 and 6 (inclusive).
What does the following code output?
java
System.out.println(Math.sqrt(9) + Math.pow(2,3));
11.0
What does the following code output?
java
System.out.println(Math.abs(Math.min(-5, 5)));
5
Identify the error in the following code:
java
int x = Math.pow(2, 3);
Math.pow() returns a double, so you need to cast it to an int or use a double variable: double x = Math.pow(2, 3); or int x = (int) Math.pow(2, 3);
Identify the error in the following code:
java
System.out.println(Math.sqrt(-4));
The code will compile and run but will return NaN (Not a Number) because you cannot take the square root of a negative number.
What does the following code output?
java
System.out.println((int)Math.random() * 10);
- The Math.random() is cast to int first, resulting in 0, then multiplied by 10.
What does the following code output?
java
int a = 5;
double b = 2.0;
System.out.println(Math.pow(a, b));
25.0
What does the following code output?
java
System.out.println(Math.abs(3 - 7.5));
4.5
What are the steps to generate a random integer between 10 and 20 (inclusive) using Math.random()?
- Calculate the range: 20 - 10 + 1 = 11. 2. Multiply Math.random() by the range: Math.random() * 11. 3. Add the minimum value: Math.random() * 11 + 10. 4. Cast the result to an integer: (int)(Math.random() * 11 + 10).
Steps to calculate distance between two points (x1, y1) and (x2, y2)?
- Find the difference in x-coordinates: (x2 - x1). 2. Find the difference in y-coordinates: (y2 - y1). 3. Square both differences. 4. Sum the squared differences. 5. Take the square root of the sum.
What are the steps to find the absolute value of a number?
- Check if the number is negative. 2. If negative, multiply by -1. 3. If non-negative, return the number as is.
Steps to calculate x to the power of y?
- Use Math.pow(x, y). 2. The method returns a double representing x raised to the power of y.
Steps to simulate a dice roll using Math.random()?
- Multiply Math.random() by 6: Math.random() * 6. 2. Add 1: Math.random() * 6 + 1. 3. Cast to an integer: (int)(Math.random() * 6 + 1).
What are the steps to use a method from the Math class?
- Identify the required method. 2. Use the syntax Math.methodName(arguments). 3. Ensure you handle the return type appropriately.
Steps to generate a random number between a (inclusive) and b (exclusive)?
- Calculate the range: b - a. 2. Multiply Math.random() by the range: Math.random() * (b - a). 3. Add the starting value: Math.random() * (b - a) + a. 4. Cast to int if needed.
Steps to find the square root of a number?
- Use Math.sqrt(number). 2. The method returns a double representing the square root of the number.