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Prime number | homework

nazis (5)
Hola, so recently I started my programming course and I am not good at it yet.
So let's get into the main problem, I have to make a program: "user inserts two numbers "m" & "n" (int m, n;)and program has to find all the prime numbers between "m" & "n"

So I am not sure how to do it, should I use some kind of an array or what, any help would be appriciated!

With much thanks
Codermik (835)

Well, assuming you know how to check for a prime number then a loop would be good here, create a loop from m to n and inside that loop check if the current loop position is a prime number and if it is then display it.

Edit: Here is a link to help you out: http://www.cplusplus.com/doc/tutorial/control/
Last edited on
nazis (5)
Thanks, btw, is an array needed to check the current loop position?
shadder (813)
No, its not mandatory

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for(int i=m;i<=n;i++)
{
cout<<i;
checkprime();
}


the output of this would be somewhat like this


5 is a prime
6 is nor a prime
7 is a prime
8 is not a prime


as you can see by checking the value of i only we can check the current loop position
Last edited on
Codermik (835)

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#include <iostream>

int main()
{

	// these are just dummy variables, in 
	// your code you would be asking the 
	// user what numbers.
	int m = 10;
	int n = 20;

	// for (initialization; condition; increase) statement;
	// so here I initialise number to m, the condition tells
	// it to loop while number is below or equal to n, and
	// lastly we say number++ to increase each time we loop
	for (int number = m; number <= n; number++)
	{
		// we loop and each time we do, the
		// number variable will increase by
		// 1

		// lets test this by displaying it.
		std::cout << number << std::endl;

	}

	return 0;
}


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nazis (5)
Hmm, mkay and where should I put the prime number checking code?
closed account (48T7M4Gy)
If you use the sieve of Eratosthenes approach an array is useful

https://en.wikipedia.org/wiki/Sieve_of_Eratosthenes
Codermik (835)

Hmm, mkay and where should I put the prime number checking code?

Where would you feel is the right logical place to test if number is a prime number?
nazis (5)
In the loop condition probably, Ty a lot guys, gona try it at home, and yea if someone have other ideas write it down, cheers
Codermik (835)

Yes, inside the Loop, you are needing to check the value of number, good luck :)
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