title: Showing an array of Doubles
body: <p>I want to write a function to transform an array of n doubles to an string, a show function, something like: </p>
  
  <pre><code>struct vec {   uint64_t n;   double *x;  };
  
  char *show(struct vec *v) {...}
  </code></pre>
  
  <p>Notice that I don't want to print them, only do a serialization into a string.</p>
  
  <p>How can I do this in C?</p>