ex03-09.cpp

数据结构常用算法合集

//EX03-09.cpp
#include <iostream.h>
#include <conio.h>
const double N=4.0;
void main()
{ double pi=N,x;
  int count=1,x314;
  cout.setf(ios::fixed,ios::floatfield);
  cout.precision(5);
  do
  { count++;
    x = (count % 2 ==0)? (-N/(count*2-1)):(N/(count*2-1));
    pi += x;
    x314=int(pi*100);
//    cout << pi<<"   "<<count<<' '<<x314<<endl;
  }
  while (x314!=314);
  cout <<int(pi*100)<<"="<<count<<"项\n";
  do
  { count++;
    x = (count % 2 ==0)? (-N/(count*2-1)):(N/(count*2-1));
    pi += x;
    x314=int(pi*1000);
//    cout << pi<<"   "<<count<<' '<<x314<<endl;
  }
  while (x314!=3141);
  cout <<int(pi*1000)<<"="<<count<<"项\n";

  do
  { count++;
    x = (count % 2 ==0)? (-N/(count*2-1)):(N/(count*2-1));
    pi += x;
    x314=int(pi*10000);
//    cout << pi<<"   "<<count<<' '<<x314<<endl;
  }
  while (x314!=31415);
  cout <<int(pi*10000)<<"="<<count<<"项\n";

  do
  { count++;
    x = (count % 2 ==0)? (-N/(count*2-1)):(N/(count*2-1));
    pi += x;
    x314=int(pi*100000);
//    cout << pi<<"   "<<count<<' '<<x314<<endl;
  }
  while (x314!=314159);
  cout <<int(pi*100000)<<"="<<count<<"项\n";
  getch();
}