Challenge 1 - SmartNumber

This is the standard "toString" method. We add to help with debugging.

We can code it just like shown here.

public String toString() {
	return "" + this.getNum();
}

getNum

Returns the ivar named num.

//Example Usage
SmartNumber sn = new SmartNumber(11);
println("SmartNumber is: " + sn.getNum());
//SmartNumber is: 11

setNum

Sets the value of the ivar named num.

//Example Usage
SmartNumber sn = new SmartNumber(11);
println(sn.toString());
//11
sn.setNum(1003);
println(sn.toString());
//1003

isEven

Returns true if our number is even, else false

Even numbers: 0, 2, 4, 6, 8, ...

//Example Usage
SmartNumber sn = new SmartNumber(12);
println("Number is even: " + sn.isEven());
//Number is even: true
sn = new SmartNumber(8097);
println("Number is even: " + sn.isEven());
//Number is even: false

isOdd

Returns true if our number is odd, else false

Odd numbers: 1, 3, 5, 7, 9, ...

//Example Usage
SmartNumber sn = new SmartNumber(12);
println("Number is even: " + sn.isOdd());
//Number is even: false
sn = new SmartNumber(8097);
println("Number is even: " + sn.isOdd());
//Number is even: true

divideAndRound

Returns the rounded result of dividing this number by the method parameter.

This method enhances Java's integer division. E.g., Java, for the integer division (9/5), will give us the result 1. The divideAndRound method will give us the intuitive result 2).

This method takes one method parameter of type long which is a divisor we divide by. Assume it will be a positive integer.

We'll return the quotient (division result) rounded to the nearest integer like the examples demonstrate.

This is how we divide and round ints in Java:

//Given primitive integers "a" and "b" (either int or long)
long q = Math.round((double)a / b);

Examples:
4/5 = 1
5/5 = 1
7/5 = 1
8/5 = 2
9/5 = 2
19/5 = 4

Example Use:
SmartNumber sn = new SmartNumber(9);
println("Result of 9/5 = " + sn.divideAndRound(5));
//Result of 9/5 = 2

isSquare

Returns true if our number is a square number

First five squares:

1
4
9
16
25
//Example Usage
SmartNumber sn = new SmartNumber(9);
println("Number is prime: " + sn.isSquare());
//Number is cube: true
sn = new SmartNumber(10);
println("Number is prime: " + sn.isSquare());
//Number is cube: false

isCube

Returns true if our number is a cube number

First five cubes:

1
8
27
64
125
//Example Usage
SmartNumber sn = new SmartNumber(125);
println("Number is prime: " + sn.isCube());
//Number is cube: true
sn = new SmartNumber(126);
println("Number is prime: " + sn.isCube());
//Number is cube: false

isSquareAndCube

Returns true if our number is a square AND a cube.

isDivisibleBy

Returns true if our number is divisible by the method parameter.

Receives one method parameter, a long, which is a candidate factor. Assume it will be a positive integer.

Note for all candidate factors greater than 10, isDivisibleBy is false.

Examples:

Number	Candidate Factor (Method Parameter)	isDivisibleBy
20	1	true
20	2	true
20	3	false
20	4	true
20	5	true
20	6	false
20	7	false
20	8	false
20	9	false
20	10	true
20	11	false
20	etc	false

squared

Returns the square of this number.

Examples:

Number	squared
1	1
2	4
3	9
4	16
5	25

cubed

Returns the cube of this number.

Examples:

Number	squared
1	1
2	8
3	27
4	64
5	125

remainder

Returns the remainder of this number divided by the method parameter.

Receives one method parameter which is a divisor to divide by, it is a long type. Assume it will be a positive integer.

Examples:

Number	divisor Method Parameter	remainder
10	1	0
10	2	0
10	3	1
10	4	2
10	5	0
10	6	4
10	7	3
10	8	2
10	9	1
10	10	0
10	11	10
10	12	10
10	13	10
10	14	10
10	15	10

roundedRatio

The roundedRatio method behaves the same way as the divideAndRound method.

See the divideAndRound definition for a description of expected method behavior, and for method return and parameter types.

See examples for divideAndRound

isPrime

Returns true if our number is a prime number, otherwise false.

A prime number has no factors excluding 1 and itself (e.g., the prime 11 has no factors greater than 1 and less than 11)

A prime number does not have any factors (excluding 1 and itself).

The number 10 is not prime because it has factors 2 and 5
The number 11 is prime because it has no factors excluding 1 and itself

If a number is a not a composite, it is a prime, and vice-versa.

We should sketch our solution ideas out on paper first -- how might we use a loop to determine if a number is prime?

First eleven primes:

2
3
5
7
11
13
17
19
23
29
31
//Example Usage
SmartNumber sn = new SmartNumber(17);
println("Number is prime: " + sn.isPrime());
//Number is prime: true
sn = new SmartNumber(18);
println("Number is prime: " + sn.isPrime());
//Number is prime: false

isComposite

Returns true if our number is a composite number, otherwise false.

A composite number has factors smaller than itself and greater than 1 (e.g., composite 10 has factors 2 x 5)

A composite number is greater than 1.

If a number is a not a prime, it is a composite, and vice-versa.

First five composites:

isPalindrome

Returns true if our number is a palindromic number, otherwise false.

A palindromic number reads the same backwards and forwards.

Careful with spelling -- isPalindrome -- best to copy-pate the method name into your code editor.

Examples:

Number	isPalindrome
1	true
2	true
10	false
11	true
107	false
151	true
87378	true

isAmicablePairWith

This method takes one param (a long) which is the other number to use to determine if our num and the param form an amicable pair.

An amicable number pair is a fun combo where the sum of the proper divisors for each equal the other number.
See the examples shown.

The sum of the proper divisors of 220 are 284.
The sum of the proper divisors of 284 are 220.
Thus 220 and 284 are amicable numbers.

Proper divisors are simply the divisors of any number excluding the number itself (but including 1).

Proper divisors of 12: 1, 2, 3, 4, 6
Proper divisors of 20: 1, 2, 4, 5, 10

num1	num2	is amicable pair?
220	284	yes
284	220	yes
2620	2924	yes
2924	2620	yes

See:

factorCount

Returns the count of all unique factors for our number. We include 1 and our number.

Example counts are shown.

Examples:

Number	Unique Factors	Factor Count
6	1, 2, 3, 6	4
9	1, 3, 9	3
11	1, 11	2
12	1, 2, 3, 4, 6, 12	6
30	1, 2, 3, 5, 6, 10, 15, 30	8

primeFactorCount

Returns the count of all unique prime factors for our number. We do not include 1 or our number in the count.

Example counts are shown.

Tip: Remember we can construct objects in a loop. E.g. you could construct a SmartNumber in a loop.

Examples:

Number	Unique Prime Factors	Prime Factor Count
6	2, 3	2
9	3	1
11	None	0
12	2, 3	2
30	2, 3, 5	3
31	None	0
210	2, 3, 5, 7	4

factorial

Returns the factorial of this number.

Do not use any Java Math library methods for your factorial computation.

A factorial is n*(n-1)*(n-2)...2*1

The factorial of 4 is:

4 * 3 * 2 * 1 = 24

The factorial of 10 is:

10 * 9 * 8 * 7 * 6 * 5 * 4 * 3 * 2 * 1 = 3628800

Note that the factorial of zero is defined to be 1

factorRatio

Returns the rounded ratio of our factorCount divided by our primeFactorCount.

If primeFactorCount is zero, then returns -1.

Examples can be derived using the examples provided for factorCount and primeFactorCount.

factorJKZ

Returns a number based on a set of rules defined below.

If we are prime, then simply return our number as-is, otherwise, we'll calculate factorJKZ using these steps:
If our number is even, let factorJKZ=2, otherwise let factorJKZ=1
Increase factorJKZ by our factorRatio (i.e. add factorRatio to factorJKZ)
If we are divisible by 3, increase factorJKZ by 3 (i.e. add 3 to factorJKZ)
If we are divisible by 5, increase factorJKZ by 5 (i.e. add 5 to factorJKZ)
If we are a square, double factorJKZ
If we are a cube, triple factorJKZ
If we are a palindrome, decrease factorJKZ by 1
Take the result of factorJKZ at this point. If this result (factorJKZ) is divisible by our number num, then multiply factorJKZ by 0.
Return the final computed result for factorJKZ

Note that this method may return any integer (i.e., negative, zero, or positive)

Examples:

Number	factorJKZ
1	0
2	2
3	3
4	9
5	5
6	0
7	7
8	17
9	13
10	9

getSummary

Return a summary string of the SmartNumber
Show one property per line
The example here shows four properties
You may use this example method as-is except add at least four more properties so that eight or more properties are displayed

public String getSummary() {
	String summary = "";
	String sep = System.lineSeparator();
	summary += "Number: " + this.getNum() + sep;
	summary += "Prime: " + this.isPrime();
	summary += "Factor Count: " + this.factorCount() + sep;
	summary += "Remainder(/10): " + this.remainder(10) + sep;
	//TODO
	return summary;
	}

Number	divisor Method Parameter	remainder
10	1	0
10	2	0
10	3	1
10	4	2
10	5	0
10	6	4
10	7	3
10	8	2
10	9	1
10	10	0
10	11	10
10	12	10
10	13	10
10	14	10
10	15	10

Number	divisor Method Parameter	remainder
10	1	0
10	2	0
10	3	1
10	4	2
10	5	0
10	6	4
10	7	3
10	8	2
10	9	1
10	10	0
10	11	10
10	12	10
10	13	10
10	14	10
10	15	10

Number	divisor Method Parameter	remainder
10	1	0
10	2	0
10	3	1
10	4	2
10	5	0
10	6	4
10	7	3
10	8	2
10	9	1
10	10	0
10	11	10
10	12	10
10	13	10
10	14	10
10	15	10