default constructor that has the option to take in a parameter?
<p>Is it possible to have 1 constructor have the option of being a default constructor if a parameter is not passed in.</p>

<p>Example, instead of having 2 constructors, where 1 is the default constructor and another is a constructor that initializes numbers passed in, is it possible to only have 1 constructor that if a value is passed in, set that value to a member function, and if no value is passed in, set the member function to a number.</p>

<p>example:</p>

<p>WEIGHT.H file:</p>

<pre><code>   class Weight
{
public:
    Weight() { size = 0; }
    Weight(int a) : size(a) {}

    int size;
};
</code></pre>

<p>MAIN.CPP file:</p>

<pre><code>int main(void)
{
  Weight w1;
  Weight w2(100);
}
</code></pre>

<p>I've been working on different school projects and they all require to have different types of constructors, and i'm wondering if there is a way to only have it once so it saves time. 
Thanks for the help. </p>
