14-9.cpp

为初学者提供的最佳的C++程序设计源程序库

#include<iostream.h>
class pwr
{
  int base;
  int exponent;
  double result;
public:
  pwr(int b,int e);
  friend ostream & operator<<(ostream & stream,pwr op);
  friend istream & operator>>(istream & stream,pwr& ob);
};
pwr::pwr(int b,int e)
{
  base=b;
  exponent=e;
  result=1;
  for(;e;e--)result=result*base;
}
ostream& operator<<(ostream& stream,pwr ob)
{
  stream<<ob.base<<"^"<<ob.exponent;
  stream<<"is"<<ob.result<<'\n';
  return stream;
}
istream & operator>>(istream& stream,pwr& ob)
{
  int b,e;
  cout<<"Enter base and exponent:";
  stream>>b>>e;
  pwr temp(b,e);
  ob=temp;
  return stream;
}
main()
{
  pwr ob(9,2);
  cout<<ob;
  cin>>ob;
  cout<<ob;
  return 0;
}