class SmallInt {
public:
  SmallInt(int i = 0): val(i)
  { 
   if (i < 0 || i > 255)
    throw std::out_of_range("Bad SmallInt initializer");
  }
  operator int() const { return val; }
private:
  std::size_t val;
};

class SmallInt {

public:

     SmallInt(int= 0);

    SmallInt(double);

//Usually it is unwise to define conversions to multiple arithmetic types

    operatorint() const { return val; }

    operatordouble() const { return val; }

private:

   std::size_tval;

};

 

void compute(int);

void fp_compute(double);

void extended_compute(long double);

SmallInt si;

compute(si); // SmallInt::operator int() const

fp_compute(si); // SmallInt::operator double() const

extended_compute(si); // error: ambiguous

void manip(const SmallInt &);

double d; int i; long l;

manip(d); // ok: use SmallInt(double) to convert theargument

manip(i); // ok: use SmallInt(int) to convert theargument

manip(l); // error: ambiguous

class Integral;

class SmallInt {

public:

SmallInt(Integral);// convert from Integral to SmallInt

};

class Integral {

public:

operatorSmallInt() const; // convert from Integral to SmallInt 

};

 

void compute(SmallInt);

Integral int_val;

compute(int_val); // error: ambiguous

compute(int_val.operator SmallInt()); // ok: useconversion operator

compute(SmallInt(int_val)); // ok: use SmallInt constructor

class SmallInt {

public:

SmallInt(constIntegral&);

};

class SmallInt {

public:

// Usually it is unwise to define conversions tomultiple

arithmetic types

operatorint() const { return val; }

operatordouble() const { return val; }

// ...

private:

std::size_tval;

};

void compute(int);

void compute(double);

void compute(long double);

SmallInt si;

compute(si); // error: ambiguous

class SmallInt {

public:

SmallInt(int= 0);

};

class Integral {

public:

Integral(int= 0);

};

void manip(const Integral&);

void manip(const SmallInt&);

manip(10); // error: ambiguous

manip(SmallInt(10)); // ok: call manip(SmallInt)

manip(Integral(10)); // ok: call manip(Integral)

class LongDouble

{

public:

     LongDouble(double );

     //…

};

void calc( int );

void calc( LongDouble );

double dval;

calc( dval ); // which function