vector::size ve vector::capacity
Nasıl kullanılacağı gösterilmiştir vector::size ve vector::capacity Visual C++ standart şablon kitaplığı (stl) işlevleri.
template<class _TYPE, class _A>
void vector::reserve(
size_type _N
);
template<class _TYPE, class _A>
size_type vector::max_size( ) const;
template<class _TYPE, class _A>
void vector::resize(
size_type _N,
_TYPE _X = _TYPE( )
);
template<class _TYPE, class _A>
size_type vector::capacity( ) const;
template<class _TYPE, class _A>
size_type vector::size( ) const;
Notlar
Not
Prototip sınıfı/parametre adları üstbilgi dosyasında sürüm eşleşmiyor.Bazıları, okumayı kolaylaştırmak için değiştirildi.
Örneği boş bir vektör tamsayılar bildirir. Vektör tek tamsayı öğesi ekler ve vector öğesinin boyutu, en büyük boyutu ve kapasitesi hakkındaki bilgileri gösterir. Bu 1.000 öğeler için depolama ortamı ayırır ve vektör hakkında bilgileri görüntüler. Son olarak, vektör 2.000 öğeleri yeniden boyutlandırılır ve bilgileri görüntüler.
Örnek
// Remax.cpp
// compile with: /EHsc
// Illustrates vector::reserve, vector::max_size,
// vector::resize, vector::resize, and vector::capacity.
//
// Functions:
//
// vector::max_size - Returns maximum number of elements vector could
// hold.
//
// vector::capacity - Returns number of elements for which memory has
// been allocated.
//
// vector::size - Returns number of elements in the vector.
//
// vector::resize - Reallocates memory for vector, preserves its
// contents if new size is larger than existing size.
//
// vector::reserve - Allocates elements for vector to ensure a minimum
// size, preserving its contents if the new size is
// larger than existing size.
//
// vector::push_back - Appends (inserts) an element to the end of a
// vector, allocating memory for it if necessary.
//
//////////////////////////////////////////////////////////////////////
// The debugger cannot handle symbols more than 255 characters long.
// STL often creates symbols longer than that.
// When symbols are longer than 255 characters, the warning is disabled.
#pragma warning(disable:4786)
#include <iostream>
#include <vector>
using namespace std ;
typedef vector<int> INTVECTOR;
int main()
{
// Dynamically allocated vector begins with 0 elements.
INTVECTOR theVector;
// Add one element to the end of the vector, an int with the value 42.
theVector.push_back(42) ;
// Show statistics about vector.
cout << "theVector's size is: " << theVector.size() << endl;
cout << "theVector's maximum size is: " << theVector.max_size()
<< endl;
cout << "theVector's capacity is: " << theVector.capacity() << endl;
// Ensure there's room for at least 1000 elements.
theVector.reserve(1000);
cout << endl << "After reserving storage for 1000 elements:" << endl;
cout << "theVector's size is: " << theVector.size() << endl;
cout << "theVector's maximum size is: " << theVector.max_size()
<< endl;
cout << "theVector's capacity is: " << theVector.capacity() << endl;
// Ensure there's room for at least 2000 elements.
theVector.resize(2000);
cout << endl << "After resizing storage to 2000 elements:" << endl;
cout << "theVector's size is: " << theVector.size() << endl;
cout << "theVector's maximum size is: " << theVector.max_size()
<< endl;
cout << "theVector's capacity is: " << theVector.capacity() << endl;
}
Örnek Çıktı
X 86 için aşağıdaki çıktıdır.
theVector's size is: 1
theVector's maximum size is: 1073741823
theVector's capacity is: 1
After reserving storage for 1000 elements:
theVector's size is: 1
theVector's maximum size is: 1073741823
theVector's capacity is: 1000
After resizing storage to 2000 elements:
theVector's size is: 2000
theVector's maximum size is: 1073741823
theVector's capacity is: 2000
Gereksinimler
Başlık: <vector>