Navigating C++ and Object-Oriented Design

5.1. Using explicit

Many constructors use single argument signatures or defaults to build class types from other types. Consider the Fifo class from Listing 4.7 on page 196, for example.

class Fifo {
private:
   char *s;                               // pointer to char data
   mutable int front;                     // read placeholder
   int rear;                              // write placeholder
   mutable int count;                     // current number of chars
   int len;                               // length
   . . .
public:
// Constructors
   Fifo(int size = Fifo_max) {            // inline constructor
      s = new char[len = size];
      front = rear = count = 0;
   }
   Fifo(const char *, int size = Fifo_max);
   . . .
};

The first Fifo constructor creates character Fifo objects with either a default length of 80 (Fifo_max) or a specified length. The second constructor builds Fifo objects from character strings ...