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1 获得容器最后一个元素 ------ 使用 back或rbegin 取得
// back、rbegin 有常量和引用两种形式
std::vector<int> myVector;
myVector.back()=3;
std::vector<int>::reverse_iterator tailIter;
tailIter=myVector.rbegin();
*tailIter=3
2 删除某元素
需要删除某位置的元素，应使用iterator遍历， 不应使用at(i) 方式遍历，因为删除元素时，是根据iterator位置进行删除的。
删除元素时，返回值为：位于删除的元素之后的第一个的元素所在的位置
MSDN解释：
Removes an element or a range of elements in a vector from specified positions.
iterator erase(
iterator _Where
);
iterator erase(
iterator _First,
iterator _Last
);
Position of the element to be removed from the vector.
_First
Position of the first element removed from the vector.
_Last
Position just beyond the last element removed from the vector.
An iterator that designates the first element remaining beyond any elements removed, or a pointer to the end of the vector if no such element exists.
MSDN示例：
#include <vector>
#include <iostream>
int main( )
{
using namespace std;
vector <int> v1;
vector <int>::iterator Iter;
v1.push_back( 10 );
v1.push_back( 20 );
v1.push_back( 30 );
v1.push_back( 40 );
v1.push_back( 50 );
cout << "v1 =" ;
for ( Iter = v1.begin( ) ; Iter != v1.end( ) ; Iter++ )
cout << " " << *Iter;
cout << endl;
v1.erase( v1.begin( ) );
cout << "v1 =";
for ( Iter = v1.begin( ) ; Iter != v1.end( ) ; Iter++ )
cout << " " << *Iter;
cout << endl;
v1.erase( v1.begin( ) + 1, v1.begin( ) + 3 );
cout << "v1 =";
for ( Iter = v1.begin( ) ; Iter != v1.end( ) ; Iter++ )
cout << " " << *Iter;
cout << endl;
}
Output
v1 = 10 20 30 40 50
v1 = 20 30 40 50
v1 = 20 50
3 两vector 容易赋值时，不能通过=来赋值
而应使用遍历 或assign函数的方式来赋值
//delNode.vectorNode 是与delPositionVector同类型容器
// vector 两容器不能直接赋值 可通过 遍历每个元素赋值，也可使用 assign赋值
VectorNode delNode;
delNode.numberOfFenkuai=nSelect;
Node nodeTemp;
错误赋值方式：
// 这是错误的赋值方式
delNode.vectorNode=delPositionVector ;
正确赋值方式一： 遍历
for (int i=0;i<delPositionVector.size();i++)
{
nodeTemp=delPositionVector.at(i);
delNode.vectorNode.push_back(nodeTemp);
}
正确赋值方式二： assign函数
delNode.vectorNode.assign(delPositionVector.begin(),delPositionVector.end());
MSDN 示例：
#include <vector>
#include <iostream>
int main( )
{
using namespace std;
vector<int> v1, v2, v3;
vector<int>::iterator iter;
v1.push_back(10);
v1.push_back(20);
v1.push_back(30);
v1.push_back(40);
v1.push_back(50);
cout << "v1 = " ;
for (iter = v1.begin(); iter != v1.end(); iter++)
cout << *iter << " ";
cout << endl;
v2.assign(v1.begin(), v1.end());
cout << "v2 = ";
for (iter = v2.begin(); iter != v2.end(); iter++)
cout << *iter << " ";
cout << endl;
v3.assign(7, 4) ;
cout << "v3 = ";
for (iter = v3.begin(); iter != v3.end(); iter++)
cout << *iter << " ";
cout << endl;
}
Output
v1 = 10 20 30 40 50
v2 = 10 20 30 40 50
v3 = 4 4 4 4 4 4 4
4 在指定的iterator位置 插入容器元素
插入某元素时，返回值为插入的那个元素所在的位置，原先处于此位置的元素将被顺次后移
MSDN： 解释及示例
iterator insert(
iterator _Where,
const Type& _Val
);
void insert(
iterator _Where,
size_type _Count,
const Type& _Val
);
template<class InputIterator>
void insert(
iterator _Where,
InputIterator _First,
InputIterator _Last
);
_Where
The position in the vector where the first element is inserted.
_Val
The value of the element being inserted into the vector.
_Count
The number of elements being inserted into the vector.
_First
The position of the first element in the range of elements to be copied.
_Last
The position of the first element beyond the range of elements to be copied.
The first insert function returns an iterator that points to the position where the new element was inserted into the vector.
Any insertion operation can be expensive, see vector Class for a discussion ofvector performance.
5 更新容器中的某个元素
办法之一： 先搜索到这个元素位置， 在此位置添加更新的元素，删除原先的元素
或搜索到此元素，删除此元素，在此元素位置上添加新元素
应用例子：
delNode.vectorNode.assign(delPositionVector.begin(),delPositionVector.end());
BOOL bInsert=FALSE;
std::vector <VectorNode>::iterator iter;
for (iter=g_DelVector.begin();iter!=g_DelVector.end();iter++)
{
if ((*iter).numberOfFenkuai==nSelect)
{
bInsert=TRUE;
//g_DelVector.erase(iter);
//g_DelVector.insert(iter,delNode);
iter=g_DelVector.insert(iter,delNode);
iter=g_DelVector.erase(iter+1);
iter--;
break;
}
}
if (!bInsert)
{
g_DelVector.push_back(delNode);
}
6 push_back或pop某元素后，迭代器会失效 需要重新获得
CSDN 论坛中例子：
STL中的vector不是关联性容器，当插入新的元素后，原来取得的迭代器就会失效。
例子如下：
std::vector<int> vNum;
vNum.push_back(1);
vNum.push_back(3);
vNum.push_back(5);
std::vector<int>::iterator pIt = vNum.begin();
std::cout << "Before insert a new number: " << *pIt << std::endl;
vNum.push_back(7);
std::cout << "After insert a new number: " << *pIt << std::endl; // Oh! No!
注意最后一句，运行到最后一句时就会发生崩溃，迭代器访问错误。插入元素后，要重新取得迭代器。
而对于map这样的关联性容器，插入新元素后，原来的迭代器仍然会有效。
例子如下：
std::map<int, int> mNum;
mNum[0] = 0;
mNum[1] = 1;
mNum[2] = 2;
std::map<int, int>::iterator pIt = mNum.begin();
std::cout << "Before insert a new number: (" << pIt->first << ", " << pIt->second << ")" << std::endl;
mNum[3] = 3;
std::cout << "After insert a new number: (" << pIt->first << ", " << pIt->second << ")" << std::endl; // OK!
7 合并两个顺序容器
std::vector<line>::iterator i1 = v1.begin(), i2 = v2.begin();
while(i1 != v1.end() && i2 != v2.end())
{
if(i1->index == i2->index)
{
line t = { i1->index, i1->value1, i2->value2 }
v3.push_back(t);
++i1;
++i2;
}
else if(i1->index > i2->index)
{
i2->value1 = 0;
v3.push_back(*i2);
++i2;
}
else
{
i1->value2 = 0;
v3.push_back(*i1);
++i1;
}
}
while(i1 != v1.end())
v3.push_back(*(i1++));
while(i2 != v2.end())
v3.push_back(*(i2++));
自己的例子：
// 删除线
std::vector<Node> delPosition;
for (int i=0;i<g_DelVector.size();i++)
{
if (g_DelVector.at(i).numberOfFenkuai==nSelect)
{
delPosition.assign(g_DelVector.at(i).vectorNode.begin(),g_DelVector.at(i).vectorNode.end());
break;
}
}
// 设置 underLine 下划线
std::vector<Node> underLinePosition;
for (int i=0;i<g_underLineVector.size();i++)
{
if (g_underLineVector.at(i).numberOfFenkuai==nSelect)
{
underLinePosition.assign(g_underLineVector.at(i).vectorNode.begin(),g_underLineVector.at(i).vectorNode.end());
break;
}
}
// 合并删除线 和 下划线 位置
Node node;
std::vector<Node> erasePosition;
std::vector<Node>::iterator i1=delPosition.begin(),i2=underLinePosition.begin();
while (i1!=delPosition.end()&&i2!=underLinePosition.end())
{
if (i1->nStart==i2->nEnd) // 合并 同时前进++
{
node.nStart=i2->nStart;
node.nEnd=i1->nEnd;
i1++;
i2++;
erasePosition.push_back(node);
continue;
}
if (i1->nEnd==i2->nStart)
{
node.nStart=i1->nStart;
node.nEnd=i2->nEnd;
i1++;
i2++;
erasePosition.push_back(node);
continue;
}
if (i1->nEnd<i2->nStart)
{
node=*i1;
i1++;
erasePosition.push_back(node);
continue;
}
if (i1->nStart>i2->nEnd)
{
node=*i2;
i2++;
erasePosition.push_back(node);
continue;
}
}
while(i1!=delPosition.end())
erasePosition.push_back(*(i1++));
while(i2!=underLinePosition.end())
erasePosition.push_back(*(i2++));
/ 整理erasePositon, 使得首尾相连的地方 进行合并
std::vector<Node>::iterator iter1,iter2;
for (iter1=erasePosition.begin();iter1!=erasePosition.end();)
{
iter2=iter1+1;
if (iter2!=erasePosition.end())
{
if (iter1->nEnd==iter2->nStart)
{
iter1->nEnd=iter2->nEnd;
iter1=erasePosition.erase(iter2);
iter1--;
continue;
}
}
iter1++;
}
trueString=_T("");
CString mixString;
GetRichEditCtrl().GetWindowText(mixString);
int nStart=0;
for (iter1=erasePosition.begin();iter1!=erasePosition.end();iter1++)
{
trueString+=mixString.Mid(nStart,iter1->nStart-nStart);
nStart=iter1->nEnd;
}
trueString+=mixString.Mid(nStart);
8 创建全局VECTOR变量，其元素仍为VECTOR类型 ---- 相当于二维数组
stdafx.h
定义数据结构，及声明变量
//-------------struct 定义的是结构 不是变量 所以不能在其前 加 extern
struct Node{
int nStart;
int nEnd;
};
struct VectorNode{
std::vector<Node> vectorNode;
int numberOfFenkuai;// 分块号
};
extern std::vector <VectorNode> g_DelVector; // 声明的是变量 ，可以加extern 表示全局变量
extern std::vector <VectorNode> g_AddVector;
stdafx.cpp 为.H中所声明的变量进行定义
#include "stdafx.h"
std::vector <VectorNode> g_DelVector;
std::vector <VectorNode> g_AddVector;
9 排序
// alg_sort.cpp
// compile with: /EHsc
#include <vector>
#include <algorithm>
#include <functional> // For greater<int>( )
#include <iostream>
// Return whether first element is greater than the second
bool UDgreater ( int elem1, int elem2 )
{
return elem1 > elem2;
}
int main( )
{
using namespace std;
vector <int> v1;
vector <int>::iterator Iter1;
int i;
for ( i = 0 ; i <= 5 ; i++ )
{
v1.push_back( 2 * i );
}
int ii;
for ( ii = 0 ; ii <= 5 ; ii++ )
{
v1.push_back( 2 * ii + 1 );
}
cout << "Original vector v1 = ( " ;
for ( Iter1 = v1.begin( ) ; Iter1 != v1.end( ) ; Iter1++ )
cout << *Iter1 << " ";
cout << ")" << endl;
sort( v1.begin( ), v1.end( ) );
cout << "Sorted vector v1 = ( " ;
for ( Iter1 = v1.begin( ) ; Iter1 != v1.end( ) ; Iter1++ )
cout << *Iter1 << " ";
cout << ")" << endl;
// To sort in descending order. specify binary predicate
sort( v1.begin( ), v1.end( ), greater<int>( ) );
cout << "Resorted (greater) vector v1 = ( " ;
for ( Iter1 = v1.begin( ) ; Iter1 != v1.end( ) ; Iter1++ )
cout << *Iter1 << " ";
cout << ")" << endl;
// A user-defined (UD) binary predicate can also be used
sort( v1.begin( ), v1.end( ), UDgreater );
cout << "Resorted (UDgreater) vector v1 = ( " ;
for ( Iter1 = v1.begin( ) ; Iter1 != v1.end( ) ; Iter1++ )
cout << *Iter1 << " ";
cout << ")" << endl;
}
Original vector v1 = ( 0 2 4 6 8 10 1 3 5 7 9 11 )
Sorted vector v1 = ( 0 1 2 3 4 5 6 7 8 9 10 11 )
Resorted (greater) vector v1 = ( 11 10 9 8 7 6 5 4 3 2 1 0 )
Resorted (UDgreater) vector v1 = ( 11 10 9 8 7 6 5 4 3 2 1 0 )
自己的例子： Vector容器 存放的CString变量
std::vector <CString> m_VectorImgName;
#include "algorithm"
BOOL STLSort(const CString &s1,const CString &s2)
{
int i,j;
CString name1=s1.Right(s1.GetLength()-s1.ReverseFind(L'\\')-1);
CString name2=s2.Right(s2.GetLength()-s2.ReverseFind(L'\\')-1);;
i=_ttoi(name1.Left(name1.Find(L'.')));
j=_ttoi(name2.Left(name2.Find(L'.')));
return i<j;
}
if(m_VectorImgName.size()>0)
{
std::sort(m_VectorImgName.begin(),m_VectorImgName.end(),STLSort);
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