need help on problem loop

[CCTHECRAW]

I can getthis to work with everything except making a number with more than one '.' invalid. What am I doing wrong? Help please.

[code]
Put the code you need help with here.
[#include <iostream>
#include <iomanip>
#include<cstring>
#include<cctype>

using namespace std;



bool isValidDouble(char[],int);
void readDouble (char[],int);

const int Size = 10;
char Numbers [Size];

bool isValidDouble (char numbers [], int size)
{
int count;
int Deccount = 0;

for (count=0;count <Size; count ++)
{ if (isdigit(Numbers[count]))
return true;
else if (((Numbers[count]) == '.') && (Deccount == 0))
{
Deccount++;
return true;
}


else
return false;


}

}

void readDouble (char Numbers[], int Size)
{
if (isValidDouble(Numbers, Size))
cout <<"That is a valid number"<<endl;
else {cout<< "That is not valid. Please retry"<<endl;}
}
void main ()
{cout<<"Please enter a real number:"<<endl;
cin.getline(Numbers,Size);
readDouble(Numbers,Size);
}