operator overloading

[EgyptianCoder]

hello every one ;
I have a little problem

// englconv.cpp
// conversions: Distance to meters, meters to Distance
#include <iostream>
using namespace std;
////////////////////////////////////////////////////////////////
class Distance                    //English Distance class
   {
   private:
      const float MTF;            //meters to feet
      int feet;
      float inches;
   public:                        //constructor (no args)
      Distance() : feet(0), inches(0.0), MTF(3.280833F)      
         {  }                     //constructor (one arg)
      Distance(float meters) : MTF(3.280833F)
         {                        //convert meters to Distance
         float fltfeet = MTF * meters;  //convert to float feet
         feet = int(fltfeet);           //feet is integer part
         inches = 12*(fltfeet-feet);    //inches is what's left
         }                        //constructor (two args)
      Distance(int ft, float in) : feet(ft), 
                                      inches(in), MTF(3.280833F)
         {  }
      void getdist()              //get length from user
         {
         cout << "\nEnter feet: ";  cin >> feet;
         cout << "Enter inches: ";  cin >> inches;
         }
      void showdist() const       //display distance
         { cout << feet << "\'-" << inches << '\"'; }

      operator float() const      //conversion operator
         {                        //converts Distance to meters
         float fracfeet = inches/12;     //convert the inches
         fracfeet += static_cast<float>(feet); //add the feet
         return fracfeet/MTF;            //convert to meters
         }
   };
////////////////////////////////////////////////////////////////
int main()
   {
   float mtrs;
   Distance dist1 = 2.35F;        //uses 1-arg constructor to
                                  //convert meters to Distance
   cout << "\ndist1 = "; dist1.showdist();

   mtrs = static_cast<float>(dist1); //uses conversion operator
                                     //for Distance to meters 
   cout << "\ndist1 = " << mtrs << " meters\n";

   Distance dist2(5, 10.25);      //uses 2-arg constructor
   
   mtrs = dist2;                  //also uses conversion op                                    
   cout << "\ndist2 = " << mtrs << " meters\n";

 //dist2 = mtrs;                  //error, = won't convert
   return 0;
   }

// strconv.cpp
// convert between ordinary strings and class String
#include <iostream>
using namespace std;
#include <string.h>             //for strcpy(), etc.
////////////////////////////////////////////////////////////////
class String                    //user-defined string type
   {
   private:
      enum { SZ = 80 };         //size of all String objects
      char str[SZ];             //holds a C-string
   public:
      String()                  //no-arg constructor
         { str[0] = '\0'; }
      String( char s[] )        //1-arg constructor
         { strcpy(str, s); }    //   convert C-string to String
      void display() const      //display the String
         { cout << str; }
      operator char*()          //conversion operator
         { return str; }        //convert String to C-string
   };
////////////////////////////////////////////////////////////////
int main()
   {
   String s1;                   //use no-arg constructor
                                //create and initialize C-string
   char xstr[] = "Joyeux Noel! ";

   s1 = xstr;                   //use 1-arg constructor
                                //   to convert C-string to String
   s1.display();                //display String

   String s2 = "Bonne Annee!";  //uses 1-arg constructor
                                //to initialize String
   cout << static_cast<char*>(s2); //use conversion operator
	cout << endl;	              //to convert String to C-string
	return 0;			           //before sending to << op
   }

line 56 in the first
the one argument constructor(for converting) isn't working but
in line 29 in the second
it is working properly why??

[EgyptianCoder]

this is a small question!