Vector构造函数
#include <iostream>
#include <vector>
#include <string>
#include <algorithm>
using namespace std;
int main()
{
string str[] = {"Alex" ,"John" ,"Robert"};
//empty vector object
vector<int> v1;
//creates vector with 10 empty elements
vector<int> v2(10);
//creates vector with 10 elements
//and assign value 0 for each
vector<int> v3(10,0);
//creates vector and assigns values from string array
vector<string> v4(str+0 ,str+3);
vector<string>::iterator sIt = v4.begin();
while(sIt != v4.end())
{
cout<<*sIt++<<" ";
}
cout<<endl;
//copy constructor
vector<string> v5(v4);
for(int i = 0;i<3;i++)
cout<<v5[i]<<" ";
cout<<endl;
return 0 ;
}
Vector.assign函数，给容器赋值;
#include <vector>
#include <algorithm>
#include <iostream>
#include <iterator>
using namespace std;
int main()
{
int ary[] = {1,2,3,4,5};
//流迭代器，针你可以把东西写的输出流中。
ostream_iterator<int> output(cout," ");
vector<int> v;
//赋值
v.assign(ary,ary+5);
copy(v.begin(),v.end(),output);
cout<<endl;
v.assign(3,100);
copy(v.begin(),v.end(),output);
cout<<endl;
return 0;
}
at()，访问容器中的元素，并且可以修改容器中的元素。
#include <vector>
#include <iostream>
#include <iterator>
using namespace std;
void main()
{
vector<int> vec(3,10);
vec[0] = 100;
vec.at(1) = 200;
ostream_iterator<int> output(cout," ");
copy(vec.begin() ,vec.end() ,output);
cout<<endl;
}
back()，返回容器的最后一个元素的引用。
#include <iostream>
#include <vector>
#include <string>
#include <iterator>
using namespace std;
//back()返回容器最后一个元素的引用,可通过它修改最后一个元素。
template<class T ,class D>
class Member
{
public:
Member(T t ,D d):name(t),sal(d){}
void print();
private:
T name;
D sal;
};
template<class T ,class D>
void Member<T,D>::print()
{
cout<<name<<" "<<sal<<endl;
}
int main()
{
typedef Member<string,double> M;
vector<M> v;
v.push_back(M("Robert",6000));
v.push_back(M("Linda",7500));
v.push_back(M("Aliens",8500));
vector<M>::iterator mIt = v.begin();
cout<<"Entire vector:"<<endl;
while(mIt != v.end())
{
(mIt++)->print();
}
cout<<endl;
cout<<"Return from back()"<<endl;
v.back()=M("china",99);
mIt = v.begin();
while(mIt != v.end())
{
(mIt++)->print();
}
cout<<endl;
return 0;
}
Resize(),调整容器的大小。size()返回容器的大小。Capacity()返回容器的容量。
#include <iostream>
#include <vector>
using namespace std;
int main()
{
vector<int> v(10,0);
cout<<"Size of v = "<<v.size()<<endl;
cout<<"Capacity of v = "<<v.capacity()<<endl;
v.resize(100);
cout<<"After resizing:"<<endl;
cout<<"Size of v = "<<v.size()<<endl;
cout<<"Capacity of v = "<<v.capacity()<<endl;
}
实验显示，返回的容量和大小一样。
clear(),清空容器中的元素
#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
template<class T>
class Print
{
public:
void operator()(T & t)
{
cout<<t<<" ";
}
};
int main()
{
vector<int> v(10);
Print<int> print;
fill(v.begin() ,v.end() ,5);
cout<<"Vector v : ";
for_each(v.begin() ,v.end() ,print);
cout<<endl;
cout<<"Size of V = "<<v.size()<<endl;
v.clear();
cout<<"Vector v : ";
for_each(v.begin() ,v.end() ,print);
cout<<endl;
cout<<"Size of V = "<<v.size()<<endl;
cout<<"Vector v is "<<(v.empty()?"":"not ");
cout<<"empty"<<endl;
}
erase(),删除指定元素，返回指定元素的下一个指针。
#include <iostream>
#include <iterator>
#include <vector>
using namespace std;
void main()
{
vector<int> v(10);
vector<int>::iterator It;
for(int i = 0 ;i < 10 ;i++)
{
v[i] = i;
}
copy(v.begin() ,v.end() ,ostream_iterator<int>(cout," "));
cout<<endl;
It = v.begin() + 2;
v.erase(It);
copy(v.begin() ,v.end() ,ostream_iterator<int>(cout ," "));
cout<<endl;
It = v.begin();
v.erase(It ,It + 2);
copy(v.begin() ,v.end() ,ostream_iterator<int>(cout ," "));
cout<<endl;
//循环查找某个元素;
It = v.begin();
for( ;It != v.end() 
{
//注意,erase()返回指向下一个元素的指针。
if(*It == 9)
It = v.erase(It);
else
It++;
}
copy(v.begin() ,v.end() ,ostream_iterator<int>(cout," "));
cout<<endl;
return ;
}
front()，返回容器的第一个元素。
#include <iostream>
#include <vector>
#include <string>
#include <iterator>
using namespace std;
template<class T ,class D>
class Member
{
public:
Member(T t ,D d):name(t),sal(d){}
void print();
private:
T name;
D sal;
};
template<class T ,class D>
void Member<T,D>::print()
{
cout<<name<<" "<<sal<<endl;
}
int main()
{
typedef Member<string ,double> M;
vector<M> v;
v.push_back(M("Linda",75000));
v.push_back(M("Robert",60000));
vector<M>::iterator It = v.begin();
cout<<"Entire vector:"<<endl;
while(It != v.end())
{
(It++)->print();
}
cout<<endl;
cout<<"Return from front()"<<endl;
v.front().print();
return 0;
}
insert() 向容器指定位置处插入元素。
#include <iostream>
#include <vector>
#include <iostream>
#include <algorithm>
#include <iterator>
using namespace std;
template<class T>
class Print
{
public:
void operator()(T & t)
{
cout<<t<<" ";
}
};
void main()
{
int ary[5];
fill(ary,ary+5,1);
vector<int> v;
vector<int>::iterator It;
Print<int> print;
copy(ary ,ary+5 ,back_inserter(v));
cout<<"vector v : ";
for_each(v.begin() ,v.end() ,print);
cout<<endl;
It = v.begin();
cout<<"v.insert(It,5) :";
v.insert(It ,5);
for_each(v.begin() ,v.end() ,print);
cout<<endl;
//Insert range ary+2 - ary+5 at the position "It"
It = v.begin() + 5;
cout<<"v.insert(It ,ary+2 ,ary+5) :";
v.insert(It ,ary+2 ,ary+5);
for_each(v.begin() ,v.end() ,print);
cout<<endl;
//Insert 2 value of "20" at the position of It
It = v.end() - 2;
v.insert(It ,2 ,20);
for_each(v.begin() ,v.end() ,print);
cout<<endl;
return ;
}
max_size()函数，返回可以增长的最大长度。
#include <iostream>
#include <vector>
using namespace std;
int main()
{
vector<int> v(10);
cout<<"Size of v = "<<v.size()<<endl;
cout<<"Max size of v = "<<v.max_size()<<endl;
return 0;
}
结果如下:
pop_back() 将容器最后面的元素弹出。（删除）
#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
template<class T>
class Print
{
public:
void operator()(T & t)
{
cout<<t<<" ";
}
};
int main()
{
vector<int> v;
Print<int> print;
for(int i = 0 ; i < 5 ;i++)
{
v.push_back(i+1);
}
while (!v.empty())
{
for_each(v.begin() ,v.end() ,print);
cout<<endl;
v.pop_back();
}
}
运行结果是：
reverse()函数，用来扩展vector的容量。
#include <iostream>
#include <vector>
#include <iterator>
using namespace std;
void main()
{
vector<int> v(5 ,0);
/*--------------------------------*/
cout<<"Size of v = "<<v.size()<<endl;
cout<<"Capacity v = "<<v.capacity()<<endl;
cout<<"Value of each element :";
copy(v.begin() ,v.end() ,ostream_iterator<int>(cout ," "));
cout<<endl;
/*--------------------------------*/
v[0] = 5;
v[1] = 8;
//automatically increases size;
v.push_back(3);
v.push_back(7);
cout<<"Size of v = "<<v.size()<<endl;
cout<<"Capacity v = "<<v.capacity()<<endl;
cout<<"Value of each element :";
copy(v.begin() ,v.end() ,ostream_iterator<int>(cout ," "));
cout<<endl;
/*--------------------------------*/
//increase capacity to 100;
v.reserve(100);
cout<<"Size of v = "<<v.size()<<endl;
cout<<"Capacity v = "<<v.capacity()<<endl;
cout<<"sizeof v = "<<sizeof(v)<<endl;
cout<<"Value of each element :";
copy(v.begin() ,v.end() ,ostream_iterator<int>(cout ," "));
cout<<endl;
}
resize()函数，调整容器的大小。若参数大于当前容器大小，可将增加的元素初始化为固定值。反之，将多余的元素从容器中删除。
#include <iostream>
#include <iterator>
#include <vector>
using namespace std;
void main()
{
vector<int> v(5);
for(int i = 0 ;i < 5 ;i++)
{
v[i] = i * 2;
}
copy(v.begin() ,v.end() ,ostream_iterator<int>(cout ," "));
cout<<endl;
//将size扩展为7个，并且将新增加的初始化为7;
v.resize(7,100);
copy(v.begin() ,v.end() ,ostream_iterator<int>(cout ," "));
cout<<endl;
//调整vector的大小为4,多余的删去;
v.resize(4);
copy(v.begin() ,v.end() ,ostream_iterator<int>(cout ," "));
cout<<endl;
return ;
}
swap()函数，交换两个容器的元素、size、capacity；
#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
template<class T>
class Print
{
public:
void operator()(T & t)
{
cout<<t<<" ";
}
};
int main()
{
int ary[] = {1 ,2 ,3 ,4 ,5 ,6 ,7 ,8 ,9 ,10};
Print<int> print;
vector<int> v1(ary,ary+7);
vector<int> v2(ary+7,ary+10);
/*=======================*/
cout<<"Vector v1 :";
for_each(v1.begin() ,v1.end() ,print);
cout<<endl;
cout<<"Size of v1 = "<<v1.size()<<endl<<endl;
cout<<"Vector v2 :";
for_each(v2.begin() ,v2.end() ,print);
cout<<endl;
cout<<"Size of v1 = "<<v2.size()<<endl<<endl;
v1.swap(v2);
cout<<"======================"<<endl;
/*=======================*/
cout<<"Vector v1 :";
for_each(v1.begin() ,v1.end() ,print);
cout<<endl;
cout<<"Size of v1 = "<<v1.size()<<endl<<endl;
cout<<"Vector v2 :";
for_each(v2.begin() ,v2.end() ,print);
cout<<endl;
cout<<"Size of v1 = "<<v2.size()<<endl<<endl;
}
