Root

Question

double root(double c)
{
double t;
t=c;

while( abs(t-c/t) > 0.001 )
t=0.5*(t+c/t);

return t;
}

Someone can help me?
The error massage tell me that I have a problem with the abs that it's not declared

Answer 1

Great! Thanx!!!

Answer 2

First number that doesn't divide into it evenly returns true.

Answer 3

So what I should write?

Answer 4

You so sharp!

Answer 5

#include <iostream>
#include <cmath>
using namespace std;

double root(double c)
{
double t;
t=c;

while( abs(t-c/t) > 0.001 )
t=0.5*(t+c/t);

return t;
}

bool Prime(int b)
{
int i;

if(b==0 || b==1)
return false;
else
for(i=2; i<root(b); i++)
{
if( b%i == 0 )
return false;
else
return true;
}

}

int main ()
{

int n;

cout<<"Please enter a num ";
cin>>n;
cout<<n<<endl;

cout<<"does your number is Primery? "<<Prime(n)<<endl;

return 0;
}

Now, can you tell me why for every number its return true?

Answer 6

I didn't understand

Answer 7

Ohh, exactly, that the problem

Answer 8

for(i=2; i<root(b); i++)
{
if( b%i == 0 )
return false;
else
return true;
}
b = 9; first loop i= 2, 9%2 is 1 so else path returns true

Answer 9

for(i=2; i<root(b); i++)
{
if( b%i == 0 )
return false;
}
return true;