fig26_09.cpp

C程序设计经典教程第5版程序示例,比较适合初级c语言的学生

// Fig. 26.9: Fig26_09.cpp 
// Controlling precision of floating-point values.
#include <iostream>
using std::cout;
using std::endl;
using std::fixed;

#include <iomanip>
using std::setprecision;

#include <cmath> 
using std::sqrt; // sqrt prototype

int main()
{
   double root2 = sqrt( 2.0 ); // calculate square root of 2
   int places; // precision, vary from 0-9

   cout << "Square root of 2 with precisions 0-9." << endl
      << "Precision set by ios_base member function "
      << "precision:" << endl;

   cout << fixed; // use fixed point format

   // display square root using ios_base function precision
   for ( places = 0; places <= 9; places++ ) 
   {
      cout.precision( places );
      cout << root2 << endl;
   } // end for

   cout << "\nPrecision set by stream manipulator " 
      << "setprecision:" << endl;

   // set precision for each digit, then display square root
   for ( places = 0; places <= 9; places++ )
      cout << setprecision( places ) << root2 << endl;

   return 0;
} // end main

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