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1. Junior Member
Join Date
Oct 2012
Posts
9

## help me

I don't know what should I doing. About cmath. Here

Code:
#include <iostream>
#include <cmath>

using namespace std;

int main() {
int n;
int i;
int is_prime = true;

cout << "Enter a number and press Enter: ";
cin >> n;

i = 2;
while (i <= sqrt(n)) {
if (n % i == 0)
is_prime = false;
i++;
}

if (is_prime)
cout << "Number is prime." << endl;
else
cout << "Number is not prime." << endl;

system("pause");
return 0;
}
Please fix it for me. Thanks

2. Junior Member
Join Date
Oct 2012
Posts
9

## Re: help me

I mean, Number 15 is error. It is said that C:\Users\Duy N. Le\Desktop\C++\prime1.cpp
call of overloaded `sqrt(int&)' is ambiguous

3. Elite Member Power Poster
Join Date
Nov 2003
Location
Florida
Posts
12,518

## Re: help me

Check the documentation for sqrt and see what type of argument it expects. Compare that to what you're passing it.

4. ## Re: help me

Do you have to use the sqrt() function?
Here's a code I did a while ago, it lists prime numbers from a given range.
It can be modified to just tell if a number is prime.
Hope it Helps
Code:
// Prime Number Notes 10-7-2011.cpp : main project file.
#include "stdafx.h"
#include <iostream>
#include "resource.h"

using namespace std;

void DisplayEvens(int, int);

int main()
{
// Declare and init two intergers
// Beginning num and ending numbers
int intBeginNum = 0;
int intEndNum = 0;

// Prompt user for range
cout << "Enter a beginning number for the range:" << endl;
cin >> intBeginNum;

cout << "Enter an ending number for the range:" << endl;
cin >> intEndNum;

DisplayEvens(intBeginNum, intEndNum);

system ("pause");
return 0;
}
void DisplayEvens(int intBeginNumDE, int intEndNumDE)
{
// Initialization and declare
// this is done inside of for loop

bool bolPrime = false;

for (int i = intBeginNumDE; i <= intEndNumDE; i++)
{

for (int j = 2; j < 10; j++)
{
if (i != j && i != 1)
{
if (i % j != 0)
bolPrime = true;
else
{
bolPrime = false;
break;
}
}
}
if (bolPrime)
cout << "Prime Number: " << i << endl;
}
return;

}

5. Junior Member
Join Date
Oct 2012
Posts
9

## Re: help me

Never mine. I already problem solved because I found out it. Show it here.

Code:
(i <= sqrt((double)n))
It would worked. :-)

6. ## Re: help me

Alright kool.

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