Determine something imposible for me...

[detroit]

I have a program inputing n number (exm.1000, 10000), and i have to get that number and figure out in a nested for loop only (No Arrays) the factor (or divisors) and after that if the factor of n number is even output = open
if its odd output = closed.

int a, b,

while (n <= SENTINEL)

for (a =1; a<= n number; a ++)

for (b=1; b<=n number; b++)// the is wrong but i cant figure out how to getthe

factors from the first for loop in the second

and the determine if they are closed or open.

I do wana say that i am having a hard time with logic behind it also,

Any advise is greatly appreciated.

Thanks for the time.

[hamsterman]

You are hard to understand. Do you want to find the number of factors or the factors themselves?

Either way,

for(int i = 0; i*i <= n; i  )
   if(n % i == 0) cout << i << " is a factor of " << n << 'n';

[lordmat]

Little confused on what you need help with but maybe this will help.

#include <iostream>
using namespace std;

int main(){

	int number = 0;

	cout << "Enter Number to be tested" << endl;

	cin >> number;
	cin.ignore();

	// i <= number /2 because no point testing past half of that number
	for(int i = 2; i <= number / 2; i  ) 
		if(number%i == 0) // if number is dividable by i than print out that it is
			cout << i << " is a factor of the number" << endl;

	if(number%2 == 0) // test if it is even because number modulate by 2 is zero if even
		cout << number << " is even" << endl;
	else
		cout << number << " is odd" << endl;
	
	cin.get();
	return 0;
}

[detroit]

first thanks for taking your time and sorry for the algorithm.

i want to find out the factors for each n number from the inner loop and from these factors

i need to figure out the factors that are even and odds.

Which determines what i am looking for.

evens = closed//this is what i need to output
odds = open // same here

Please, i am having a very hard time with this program and any help is appreciated

Again thanks for your time and help

[detroit]

Hi everyone thanks for the time and help

just wanted to add that

n number input from end user represents lockers

and the sample down is what i got this far

Thanks for the time everyone

[detroit]

// Purpose: This program is a game that requires an input for a n lockers.
// After the input the first sudent will open the lockers.
// Then the second student will close all the even-numberd lockers.
// Then the third student will chek every third locker
// if it's open it will close if it's closed it will open it.
// So every (n)-th student will check (n)-th locker and close
// it if it's open and open if its closed.
// When this program is over, it should print the total lockers
// that are open and the number of the lockers that are open.
//
// Input: The number of lockers.
//
// Output: The total lockers that are open.
// The number of the lockers that are open.
//
//********************************************************************************

// include statement(s).
#include <iostream>
#include <cmath>
#include <iomanip>

// using namespace statement.
using namespace std;
// Declare named constants, if necessary.
const int SENTINEL = -999;
int main()
{
int numLockers; //number of lockers
int a; //first for loop use
int b; //secon for loop use
int total; //tTotal lockers open

cout <<"Enter the number of the lockers: ";
cin >> numLockers;
cout <<"The number you entered is: " << numLockers << endl;

//while (n != SENTINEL)

for(a=1; a<=numLockers; a )
//cout << setw(3) << a << endl;

for (b=2; b<=a/2; b)// from this point on i cant seem to go any further

if(??)
output?


return 0;
}

[ne555]

So you want to count how many numbers between 1 and n, have an odd number of factors.
Change your approach. When a number will have an odd quantity of factors?

Hint: if p is a factor of n then q = n/p is also a factor of n.

Edit: [code]"Please use code tags"[/code]

[detroit]

Thanks for posting in this topic.

Can you please elaborate on what aproach i should take in regards to the one i posted.

I'm sory but i do not understand the hint you gave me.

for (a=1; a=number; a )//here i see all the numbers i get that.

for (?;?;?)
      
                if(??)

//on the second for how do i get each number and factorise it and determine if is even or odd.

i do not know how.

Please i need a jump start...

[ne555]

Suppose that you find a divisor of n. Then n/p = q equivalent to n = p*q
But then q is also a divisor of n.
So, when you find a divisor you actually find 2 divisors (p and q)
Example: 2 is a divisor of 6, and 6/2=3 is also a divisor of 6

So you could be tempted to say: all numbers have an even amount of divisors.
But that will be wrong, as it is easy to provide a counterexample 4 has as divisors 1, 2, 4 only 3 divisors (and odd number)
Now, what make 4 so especial?

[detroit]

A locker is closed if the locker number has an even number of factors.

so is stated in the problem. In the above example there are 3 total factors so its odd

odd = open locker

now if it was 4 total divisors then it's even 8 has four divisors 1, 2, 4, 8,

even = closed locker

How to get the divisors i do not know?

Thanks for your patience and time.