1、empty——判断容器内元素是否为空
#include <iostream>
#include <vector>
using namespace std;
int main ()
{
vector<int> v;
cout << "Vector is ";
v.empty() ? cout << "" : cout << "not ";
cout << "empty" << endl;
v.push_back(100);
cout << "Vector is ";
v.empty() ? cout << "" : cout << "not ";
cout << "empty" << endl;
return 0;
}
运行结果：
// Vector is empty
// Vector is not empty
2、end——容器迭代器最后一个元素的下一个迭代
#include <iostream>
#include <vector>
#include <iterator>
#include <numeric>
using namespace std;
int main ()
{
vector<int> v(5);
iota(v.begin(),v.end(),1);
vector<int>::iterator It = v.begin();
while ( It != v.end() )
cout << *It++ << " ";
cout << endl;
// vector容器的最后一个元素
It = v.end()-1;
cout << *It << endl;
return 0;
}
运行结果:
// 1 2 3 4 5
// 5
3、erase——从容器中删除某个元素或者某个区间
#include <iostream>
#include <vector>
#include <iterator>
#include <algorithm>
using namespace std;
int main ()
{
vector<int> v(10);
vector<int>::iterator It;
for ( int i=0; i<10; i++ )
v[i] = i+1;
copy(v.begin(),v.end(),
ostream_iterator<int>(cout," "));
cout << endl;
It = v.begin()+2;
// 删除第三个元素
v.erase(It);
copy(v.begin(),v.end(),
ostream_iterator<int>(cout," "));
cout << endl;
It = v.begin();
// 从v容器中删除前两个元素
v.erase(It,It+2);
copy(v.begin(),v.end(),
ostream_iterator<int>(cout," "));
cout << endl;
return 0;
}
运行结果:
// 1 2 3 4 5 6 7 8 9 10
// 1 2 4 5 6 7 8 9 10
// 4 5 6 7 8 9 10
4、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::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;
}
运行结果:
// Entire vector:
// Linda 75000
// Robert 60000
//
// Return from front()
// Linda 75000
5、insert——想容器中插入一个、多个或者一组元素
#include <iostream>
#include <vector>
#include <iterator>
#include <algorithm>
using namespace std;
template <class T>
class Print
{
public:
void operator () (T& t)
{
cout << t << " ";
}
};
//=============================
int 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();
// 将5插入容器的It位置
cout << "v.insert(It,5) : ";
v.insert(It,5);
for_each(v.begin(),v.end(),print);
cout << endl;
// 将区间【ary+2 - ary+5】插入位置"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;
// 将2个20插入"It"位置
It = v.end()-2;
cout << "v.insert(It,2,20) : ";
v.insert(It,2,20);
for_each(v.begin(),v.end(),print);
cout << endl;
return 0;
}
运行结果:
// vector v : 1 1 1 1 1
// v.insert(It,5) : 5 1 1 1 1 1
// v.insert(It,ary+2,ary+5 : 5 1 1 1 1 1 1 1 1
// v.insert(It,2,20) : 5 1 1 1 1 1 1 20 20 1
6、max_size——容器能申请到的最大容量
#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;
}
运行结果:
// Size of v = 10
// Max_size of v = 1073741823
7、pop_back——让容器的最后一个元素出栈
#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();
}
return 0;
}
运行结果:
// 1 2 3 4 5
// 1 2 3 4
// 1 2 3
// 1 2
// 1
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