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copied!<p>From the standard. "To default-initialize an object of type T means: -- if T is a non-POD class type [the case like vector], the default constructor for T is called."</p> <p>The constructor notation <code>T()</code> is used to express the default value of type T and that this is zero for built in types and the default constructor for user-defined types. The construct <code>POD()</code> produces value initialisation and according to the stdandard, which results in all members and sub members being either default constructed or zero initialised.</p> <p>This is why your statement is legal, but is it zero initialized as per the standard; needs some detailed lookup IMHO.</p> <p>BUT, i could not find in the standard where the it <strong>defines</strong> the <em>meaning of default construction for built in types</em>.</p> <p><strong>EDIT:-</strong></p> <pre><code>struct S { int x; }; void f () { S s1; // s1.x is uninitialized here S s2 = S(); // s2.x is zero here } </code></pre> <p>I think we often make up our own interpretation of what default construction applied to built in types means; because the C++ standard doesn't define it (atleast i could not find it) and i remember <em>Stroustrup</em> or <em>Josuttis</em> say that it means <code>T()</code> which is described as being value initialisation is "<strong>zero converted to type T</strong>" for built in types.</p> <p>Since <code>int*</code> is a built-in type it is initialized to zero.</p> <p>But i am really not sure.</p>

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