/*
* vectorDemo.cpp
*
* Created on: Jul 17, 2014
* Author: lichfeng
*/
#include<vector>
#include <iostream.h>
#include <algorithm>
#include"vectorDemo.H"
using namespace std;
void vectorDemo() {
/**************************************************************************/
/* constructors functions */
/**************************************************************************/
vector<int> first; // empty vector of ints
vector<int> second(4, 100); // four ints with value 100
vector<int> third(second.begin(), second.end()); // iterating through second
vector<int> fourth(third); // a copy of third
// the iterator constructor can also be used to construct from arrays:
int myints[] = { 16, 2, 77, 29, 8, 3, 24 };
vector<int> fifth(myints, myints + sizeof(myints) / sizeof(int));
cout << "The contents of fifth are:";
for (vector<int>::iterator it = fifth.begin(); it != fifth.end(); ++it)
cout << ' ' << *it;
cout << '\n';
/**************************************************************************/
/* iterator erase (iterator position); */
/* iterator erase (iterator first, iterator last); */
/* erase(): 在vector中移除一个元素（通过position），或者移除一个区间（[first, last)）内的元素*/
/* 该函数返回值是所删除的元素的下一个元素。 */
/* Note: 由于vector是以数组形式组织的，所以删除中间元素将导致vector中其他元素向前移动。这对vector */
/* 而言是低效的操作，应减少使用。但此操作对list和deque等链表组织的容器很高效. */
/**************************************************************************/
//vector<int>::iterator ii;
fifth.erase(fifth.begin() + 1);
cout << "After erase by position, the contents of fifth are:";
for (vector<int>::iterator it = fifth.begin(); it != fifth.end(); ++it)
cout << ' ' << *it;
cout << '\n';
fifth.erase(fifth.begin(), fifth.begin() + 2);
cout << "After erase by range, the contents of fifth are:";
for (vector<int>::iterator it = fifth.begin(); it != fifth.end(); ++it)
cout << ' ' << *it;
cout << '\n';
/***************************************************************************/
/* capacity(): 返回当前vector已分配的存储空间大小（按照所存元素类型），该值大于等于size（） */
/* size(): 返回当前vector所实际存储的元素数目 */
/* max_size(): 该vector可以分配的最大内存空间（操作系统限制的） */
/* push_back():在vector末尾增加一个元素，将导致size数加1。当且仅当size数大于当前容量时， */
/* 引起vector内存重新分配（按内存非配器算法增加vector容量 */
/* pop_back(): 移除vector的最后一个元素，引起size减少1 */
/* begin(): 返回指向vector第一个元素的iterator */
/* end(): 返回指向vector最后一个元素的下一个元素的iterator， 不能取值。 */
/* cbegin(): 返回指向vector第一个元素的const iterator,不允许修改vector数据 */
/* cend(): 返回指向vector最后一个元素的下一个元素的const iterator， 不能取值。 */
/* at(): 返回at(position)中position的引用. */
/* front(): 返回vector第一個元素的引用. */
/* back(): 返回vector中最后一个元素的引用. */
/* clear(): 移除vector中所有的元素，将导致vector size为0.（capacity非强制变化）. */
/**************************************************************************/
vector<int> vIntTest;
cout << "0：The size is " << vIntTest.size() << endl;
cout << "0:The capacity is " << vIntTest.capacity() << endl;
cout << "0:The max capacity is " << vIntTest.max_size() << endl;
for (int i = 0; i < 10; i++)
vIntTest.push_back(i);
cout << "1：The size is " << vIntTest.size() << endl;
cout << "1:The capacity is " << vIntTest.capacity() << endl;
vIntTest.pop_back();
cout << "2：The size is " << vIntTest.size() << endl;
cout << "2:The capacity is " << vIntTest.capacity() << endl;
vIntTest.insert(vIntTest.end(), 10, 100);
cout << "3：The size is " << vIntTest.size() << endl;
cout << "3:The capacity is " << vIntTest.capacity() << endl;
vIntTest.at(0) = 100;
vIntTest.at(1) = 200;
cout << "After set by at():";
for (vector<int>::iterator it = fifth.begin(); it != fifth.end(); ++it)
cout << ' ' << *it;
cout << '\n';
vIntTest.back() = 1000;
cout << "After set by back():";
for (vector<int>::iterator it = fifth.begin(); it != fifth.end(); ++it)
cout << ' ' << *it;
cout << '\n';
/***************************************************************************/
/* rbegin(): 返回指向vector最后一个元素的迭代器，对翻转迭代器加操作将导致其向前移动. */
/* empty(): 判斷vector是否為空并返回，空返回true，非空返回false */
/* resize(): 調整容器的size以包含n個元素，移除多餘的元素或增大內存空間 */
/* reserve(): 要求vector capacity至少包含n個元素，如果n大于當前capacity，vector容量將增加 */
/***************************************************************************/
vector<int> reserveVec(5);
vector<int>::reverse_iterator ri;
int i=0;
for(ri=reserveVec.rbegin(); ri!=reserveVec.rend(); ri++)
{
*ri = ++i;
}
cout<<"reserveVec contains: ";
for(vector<int>::iterator it= reserveVec.begin(); it != reserveVec.end(); it++)
cout<<"*it ";
cout<<endl;
/***************************************************************************/
/* data(): 返回vector首元素的内部C类型指针，通过该指针完成所有的操作. */
/* empty(): 判斷vector是否為空并返回，空返回true，非空返回false */
/* resize(): 調整容器的size以包含n個元素，移除多餘的元素或增大內存空間 */
/* reserve(): 要求vector capacity至少包含n個元素，如果n大于當前capacity，vector容量將增加 */
/***************************************************************************/
//data()
/*vector<int> myvector(5);
int* p = myvector.data();
*p = 10;
++p;
*p = 20;
p[2] = 100;
cout << "myvector contains:";
for (unsigned i = 0; i < myvector.size(); ++i)
cout << ' ' << myvector[i];
cout << '\n';*/
// reserve()
vector<int>::size_type sz;
vector<int> foo;
sz = foo.capacity();
std::cout << "making foo grow:\n";
for (int i = 0; i < 100; ++i) {
foo.push_back(i);
if (sz != foo.capacity()) {
sz = foo.capacity();
cout << "capacity changed: " << sz << '\n';
}
}
vector<int> bar;
sz = bar.capacity();
bar.reserve(100); // this is the only difference with foo above
cout << "making bar grow:\n";
for (int i = 0; i < 100; ++i) {
bar.push_back(i);
if (sz != bar.capacity()) {
sz = bar.capacity();
cout << "capacity changed: " << sz << '\n';
}
}
//resize
vector<int> myvector1;
// set some initial content:
for (int i = 1; i < 10; i++)
myvector1.push_back(i);
myvector1.resize(5);
myvector1.resize(8, 100);
myvector1.resize(12);
cout << "myvector contains:";
for (int i = 0; i < myvector1.size(); i++)
cout << ' ' << myvector1[i];
cout << '\n';
//myvector contains: 1 2 3 4 5 100 100 100 0 0 0 0
}
