C++ Tutorial/vector/vector find — различия между версиями
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Версия 14:21, 25 мая 2010
Содержание
Demonstrating the generic find algorithm with a vector
#include <iostream>
#include <cassert>
#include <vector>
#include <algorithm> // For find
using namespace std;
int main()
{
char x[5] = {"a", "b", "c", "d", "f"};
vector<char> vector1(&x[0], &x[5]);
// Search for the first occurrence
vector<char>::iterator where = find(vector1.begin(), vector1.end(), "b");
cout << *where << endl;
return 0;
}
b
Find a sample integer "3" in the vector using the "find" algorithm
#include <algorithm>
#include <vector>
#include <iostream>
using namespace std;
template <typename elementType>
bool IsEven (const elementType& number)
{
return ((number % 2) == 0);
}
int main ()
{
vector <int> v;
for (int nNum = -9; nNum < 10; ++ nNum)
v.push_back (nNum);
vector <int>::const_iterator i;
for ( i = v.begin (); i != v.end (); ++ i )
cout << *i << " ";
cout << v.size () << "" elements" << endl;
// Find a sample integer "3" in the vector using the "find" algorithm
vector <int>::iterator iFound;
iFound = find ( v.begin () // Start of range
, v.end () // End of range
, 3 ); // Element to find
return 0;
}
Find the first even number in the collection
#include <algorithm>
#include <vector>
#include <iostream>
using namespace std;
template <typename elementType>
bool IsEven (const elementType& number)
{
return ((number % 2) == 0);
}
int main ()
{
vector <int> v;
for (int nNum = -9; nNum < 10; ++ nNum)
v.push_back (nNum);
vector <int>::const_iterator i;
for ( i = v.begin (); i != v.end (); ++ i )
cout << *i << " ";
cout << v.size () << "" elements" << endl;
// Find the first even number in the collection
vector <int>::iterator iEvenNumber;
iEvenNumber = find_if ( v.begin ()// Start of range
, v.end () // End of range
, IsEven <int> ); // Unary Predicate
if (iEvenNumber != v.end ())
{
cout << "Number "" << *iEvenNumber << "" found at position [";
cout << distance (v.begin (), iEvenNumber);
cout << "]" << endl;
}
return 0;
}
find the smallest number
#include <algorithm>
#include <iostream>
#include <vector>
using namespace std;
template <class T>
void print(T& c){
for( typename T::iterator i = c.begin(); i != c.end(); i++ ){
std::cout << *i << endl;
}
}
int main( )
{
vector<double> v( 5, 2.78 );
v[2] = 0.0;
// make the vector as large as possible without reallocating
v.resize( v.capacity(), 2.78 );
// find the smallest number
vector<double>::iterator before_itr = min_element( v.begin(), v.end() );
}
Locate maximum element in a vector
#include <iostream>
using std::cout;
using std::endl;
#include <algorithm>
#include <numeric>
#include <vector>
#include <iterator>
int main()
{
std::ostream_iterator< int > output( cout, " " );
int a2[ 10 ] = { 100, 2, 8, 1, 50, 3, 8, 8, 9, 10 };
std::vector< int > v2( a2, a2 + 10 ); // copy of a2
cout << "\n\nVector v2 contains: ";
std::copy( v2.begin(), v2.end(), output );
// locate maximum element in v2
cout << "\nMaximum element in Vector v2 is: "
<< *( std::max_element( v2.begin(), v2.end() ) );
cout << endl;
return 0;
}
Vector v2 contains: 100 2 8 1 50 3 8 8 9 10 Maximum element in Vector v2 is: 100
Locate minimum element in a vector
#include <iostream>
using std::cout;
using std::endl;
#include <algorithm>
#include <numeric>
#include <vector>
#include <iterator>
int main()
{
std::ostream_iterator< int > output( cout, " " );
int a2[ 10 ] = { 100, 2, 8, 1, 50, 3, 8, 8, 9, 10 };
std::vector< int > v2( a2, a2 + 10 ); // copy of a2
cout << "\n\nVector v2 contains: ";
std::copy( v2.begin(), v2.end(), output );
// locate minimum element in v2
cout << "\n\nMinimum element in Vector v2 is: "
<< *( std::min_element( v2.begin(), v2.end() ) );
cout << endl;
return 0;
}
Vector v2 contains: 100 2 8 1 50 3 8 8 9 10 Minimum element in Vector v2 is: 1