vector::reserve (STL/CLR)

Article
06/05/2017

The new home for Visual Studio documentation is Visual Studio 2017 Documentation on docs.microsoft.com.

The latest version of this topic can be found at vector::reserve (STL/CLR).

Ensures a minimum growth capacity for the container.

Syntax

void reserve(size_type count);

Parameters

count
New minimum capacity of the container.

Remarks

The member function ensures that capacity() henceforth returns at least count. You use it to ensure that the container need not reallocate storage for the controlled sequence until it has grown to the specified size.

Example

// cliext_vector_reserve.cpp   
// compile with: /clr   
#include <cliext/vector>   
  
int main()   
    {   
    cliext::vector<wchar_t> c1;   
    c1.push_back(L'a');   
    c1.push_back(L'b');   
    c1.push_back(L'c');   
  
// display initial contents " a b c"   
    for (int i = 0; i < c1.size(); ++i)   
        System::Console::Write(" {0}", c1.at(i));   
    System::Console::WriteLine();   
  
// increase capacity   
    cliext::vector<wchar_t>::size_type cap = c1.capacity();   
    System::Console::WriteLine("capacity() = {0}, ok = {1}",   
        cap, c1.size() <= cap);   
    c1.reserve(cap + 5);   
    System::Console::WriteLine("capacity() = {0}, ok = {1}",   
        c1.capacity(), cap + 5 <= c1.capacity());   
    return (0);   
    }

 a b c  
capacity
() = 4, ok = True  
capacity
() = 9, ok = True

Description

Note that the actual capacities may differ from the values shown here, so long as all ok tests report true.

Requirements

Header: <cliext/vector>

Namespace: cliext

Partager via