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STL 中定义了5种迭代器：输入，输出，向前，双向，随机访问，所有迭代器都具备操作符==，！=，和解引用操作符*。
算法reverse:将线性表的y元素逆置。
reverse ( y.begin( ),y.end( ) );
算法accumulate:对线性表的y元素求和。
int sum = accumulate( y.begin ( ),y.end ( ),0 );
容器 vector:一个基于数组的类。
vector test 笔记：
main.cpp:
// test the class vectorList that uses a vector for the list elements
#include<iostream>
#include<numeric>
#include<algorithm> // has reverse
#include<functional> // has greater
#include "linearList.h"
#include "vectorList.h"
using namespace std;
int main()
{
// test constructor
linearList<double> *x = new vectorList<double>(20);
vectorList<int> y(2), z;
// test capacity
cout << "Capacity of x, y and z = "
<< ((vectorList<double>*) x)->capacity() << ", "
<< y.capacity() << ", "
<< z.capacity() << endl;
// test size
cout << "Initial size of x, y, and z = "
<< x->size() << ", "
<< y.size() << ", "
<< z.size() << endl;
// test empty
if (x->empty()) cout << "x is empty" << endl;
else cout << "x is not empty" << endl;
if (y.empty()) cout << "y is empty" << endl;
else cout << "y is not empty" << endl;
// test insert
y.insert(0, 2);
y.insert(1, 6);
y.insert(0, 1);
y.insert(2, 4);
y.insert(3, 5);
y.insert(2, 3);
cout << "Inserted 6 integers, list y should be 1 2 3 4 5 6" << endl;
cout << "Size of y = " << y.size() << endl;
cout << "Capacity of y = " << y.capacity() << endl;
if (y.empty()) cout << "y is empty" << endl;
else cout << "y is not empty" << endl;
y.output(cout);
cout << endl << "Testing overloaded <<" << endl;
cout << y << endl;
// test indexOf
int index = y.indexOf(4);
if (index < 0) cout << "4 not found" << endl;
else cout << "The index of 4 is " << index << endl;
index = y.indexOf(7);
if (index < 0) cout << "7 not found" << endl;
else cout << "The index of 7 is " << index << endl;
// test get
cout << "Element with index 0 is " << y.get(0) << endl;
cout << "Element with index 3 is " << y.get(3) << endl;
// test erase
y.erase(1);
cout << "Element 1 erased" << endl;
cout << "The list is " << y << endl;
y.erase(2);
cout << "Element 2 erased" << endl;
cout << "The list is " << y << endl;
cout << "Size of y = " << y.size() << endl;
cout << "Capacity of y = " << y.capacity() << endl;
if (y.empty()) cout << "y is empty" << endl;
else cout << "y is not empty" << endl;
try {y.insert(-3, 0);}
catch (illegalIndex e)
{
cout << "Illegal index exception" << endl;
cout << "Insert index must be between 0 and list size" << endl;
e.outputMessage();
}
// test copy constructor
vectorList<int> w(y);
y.erase(0);
y.erase(0);
cout << "w should be old y, new y has first 2 elements removed" << endl;
cout << "w is " << w << endl;
cout << "y is " << y << endl;
// a few more inserts, just for fun
y.insert(0,4);
y.insert(0,5);
y.insert(0,6);
y.insert(0,7);
cout << "y is " << y << endl;
// test iterator
cout << "Ouput using forward iterators pre and post ++" << endl;
for (vectorList<int>::iterator i = y.begin();
i != y.end(); i++)
cout << *i << " ";
cout << endl;
for (vectorList<int>::iterator i = y.begin();
i != y.end(); ++i)
cout << *i << " ";
cout << endl;
cout << "Ouput using backward iterators pre and post --" << endl;
for (vectorList<int>::iterator i = y.end();
i != y.begin(); cout << *(--i) << " ");
cout << endl;
for (vectorList<int>::iterator i = y.end();
i != y.begin();)
{i--; cout << *i << " "; *i += 1;}
cout << endl;
cout << "Incremented by 1 list is " << y << endl;
// try out some STL algorithms
reverse(y.begin(), y.end());
cout << "The reversed list is " << y << endl;
int sum = accumulate(y.begin(), y.end(), 0);
cout << "The sum of the elements is " << sum << endl;
sort(y.begin(), y.end());
cout << "The sorted list is " << y << endl;
sort(y.begin(), y.end(), greater<int>());
cout << "The list is descending order is " << y << endl;
return 0;
}
下面是vector.h:
#ifndef vectorList_
#define vectorList_
#include<iostream>
#include<sstream>
#include<string>
#include<vector>
#include<algorithm>
#include<iterator>
#include "linearList.h"
#include "myExceptions.h"
using namespace std;
template<class T>
class vectorList : public linearList<T>
{
public:
// constructor, copy constructor and destructor
vectorList(int initialCapacity = 10);
vectorList(const vectorList<T>&);
~vectorList() {delete element;}
// ADT methods
bool empty() const {return element->empty();}
int size() const {return (int) element->size();}
T& get(int theIndex) const;
int indexOf(const T& theElement) const;
void erase(int theIndex);
void insert(int theIndex, const T& theElement);
void output(ostream& out) const;
// additional method
int capacity() const {return (int) element->capacity();}
// iterators to start and end of list
typedef typename vector<T>::iterator iterator;
iterator begin() {return element->begin();}
iterator end() {return element->end();}
protected: // additional members of vectorList
void checkIndex(int theIndex) const;
vector<T>* element; // vector to hold list elements
};
template<class T>
vectorList<T>::vectorList(int initialCapacity)
{// Constructor.
if (initialCapacity < 1)
{ostringstream s;
s << "Initial capacity = " << initialCapacity << " Must be > 0";
throw illegalParameterValue(s.str());
}
element = new vector<T>;
// create an empty vector with capacity 0
element->reserve(initialCapacity);
// increase vector capacity from 0 to initialCapacity
}
template<class T>
vectorList<T>::vectorList(const vectorList<T>& theList)
{// Copy constructor.
element = new vector<T>(*theList.element);
}
template<class T>
void vectorList<T>::checkIndex(int theIndex) const
{// Verify that theIndex is between 0 and size() - 1.
if (theIndex < 0 || theIndex >= size())
{ostringstream s;
s << "index = " << theIndex << " size = " << size();
throw illegalIndex(s.str());
}
}
template<class T>
T& vectorList<T>::get(int theIndex) const
{// Return element whose index is theIndex.
// Throw illegalIndex exception if no such element.
checkIndex(theIndex);
return (*element)[theIndex];
}
template<class T>
int vectorList<T>::indexOf(const T& theElement) const
{// Return index of first occurrence of theElement.
// Return -1 if theElement not in list.
// search for theElement
int theIndex = (int) (find(element->begin(), element->end(),
theElement)
- element->begin());
// check if theElement was found
if (theIndex == size())
// not found
return -1;
else return theIndex;
}
template<class T>
void vectorList<T>::erase(int theIndex)
{// Delete the element whose index is theIndex.
// Throw illegalIndex exception if no such element.
checkIndex(theIndex);
element->erase(begin() + theIndex);
}
template<class T>
void vectorList<T>::insert(int theIndex, const T& theElement)
{// Insert theElement so that its index is theIndex.
if (theIndex < 0 || theIndex > size())
{// invalid index
ostringstream s;
s << "index = " << theIndex << " size = " << size();
throw illegalIndex(s.str());
}
element->insert(element->begin() + theIndex, theElement);
// may throw an uncaught exception if insufficient
// memory to resize vector
}
template<class T>
void vectorList<T>::output(ostream& out) const
{// Put the list into the stream out.
copy(element->begin(), element->end(), ostream_iterator<T>(cout, " "));
}
// overload <<
template <class T>
ostream& operator<<(ostream& out, const vectorList<T>& x)
{x.output(out); return out;}
#endif下面是LinearList.h
#ifndef linearList_
#define linearList_
#include <iostream>
using namespace std;
template<class T>
class linearList
{
public:
virtual ~linearList() {};
virtual bool empty() const = 0;
// return true iff list is empty
virtual int size() const = 0;
// return number of elements in list
virtual T& get(int theIndex) const = 0;
// return element whose index is theIndex
virtual int indexOf(const T& theElement) const = 0;
// return index of first occurence of theElement
virtual void erase(int theIndex) = 0;
// remove the element whose index is theIndex
virtual void insert(int theIndex, const T& theElement) = 0;
// insert theElement so that its index is theIndex
virtual void output(ostream& out) const = 0;
// insert list into stream out
};
#endif