fig23_30.cpp

是有关C++编程原理教程的例子程序,全,应该对大家有所帮助

// Fig. 23.30: Fig23_30.cpp
// Mathematical algorithms of the Standard Library.
#include <iostream>
using std::cout;
using std::endl;

#include <algorithm> // algorithm definitions  
#include <numeric> // accumulate is defined here
#include <vector>
#include <iterator> 

bool greater9( int ); // predicate function prototype
void outputSquare( int ); // output square of a value
int calculateCube( int ); // calculate cube of a value

int main()
{
   const int SIZE = 10;
   int a1[ SIZE ] = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };
   std::vector< int > v( a1, a1 + SIZE ); // copy of a1
   std::ostream_iterator< int > output( cout, " " );

   cout << "Vector v before random_shuffle: ";
   std::copy( v.begin(), v.end(), output );

   std::random_shuffle( v.begin(), v.end() ); // shuffle elements of v
   cout << "\nVector v after random_shuffle: ";
   std::copy( v.begin(), v.end(), output );

   int a2[ SIZE ] = { 100, 2, 8, 1, 50, 3, 8, 8, 9, 10 };
   std::vector< int > v2( a2, a2 + SIZE ); // copy of a2
   cout << "\n\nVector v2 contains: ";
   std::copy( v2.begin(), v2.end(), output );
 
   // count number of elements in v2 with value 8
   int result = std::count( v2.begin(), v2.end(), 8 );
   cout << "\nNumber of elements matching 8: " << result;
 
   // count number of elements in v2 that are greater than 9
   result = std::count_if( v2.begin(), v2.end(), greater9 );
   cout << "\nNumber of elements greater than 9: " << result;

   // locate minimum element in v2
   cout << "\n\nMinimum element in Vector v2 is: "
      << *( std::min_element( v2.begin(), v2.end() ) );

   // locate maximum element in v2
   cout << "\nMaximum element in Vector v2 is: "
      << *( std::max_element( v2.begin(), v2.end() ) );

   // calculate sum of elements in v
   cout << "\n\nThe total of the elements in Vector v is: "
      << std::accumulate( v.begin(), v.end(), 0 );

   // output square of every element in v
   cout << "\n\nThe square of every integer in Vector v is:\n";
   std::for_each( v.begin(), v.end(), outputSquare ); 

   std::vector< int > cubes( SIZE ); // instantiate vector cubes
   
   // calculate cube of each element in v; place results in cubes
   std::transform( v.begin(), v.end(), cubes.begin(), calculateCube );
   cout << "\n\nThe cube of every integer in Vector v is:\n";
   std::copy( cubes.begin(), cubes.end(), output );
   cout << endl;
   return 0;
} // end main

// determine whether argument is greater than 9
bool greater9( int value ) 
{ 
   return value > 9; 
} // end function greater9

// output square of argument
void outputSquare( int value ) 
{ 
   cout << value * value << ' '; 
} // end function outputSquare

// return cube of argument
int calculateCube( int value ) 
{ 
   return value * value * value; 
} // end function calculateCube

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