STL中的deque容器

deque全称为“double-ended queue”，是一种动态数组形式，是一种随机访问的数据类型，是一种双端队列容器。它的重要特征就是在deque的两端放置元素和删除元素是高效的，而vector对象只有在其尾部执行操作时才有较高的效率。deque有五中初始化方式：

1.deque<A> name; 2.deque<A>name(size); 3.deque<A>name(size,value); 4.deque<A>name(mydeque); 5.deque<A>name(first, last);

#include <string>

#include <deque>

#include <iostream>

#include<algorithm>

void main (void)

{ std:: deque<std::string> Mydeque;

Mydeque.push_back("good!");

Mydeque.insert(find(Mydeque.begin(),Mydeque.end(),"good!"),"YCL");

copy(Mydeque.begin(),Mydeque.end(),std::ostream_iterator<std::string>(std::cout," "));

}

///////////////遍历deque元素////////////////////

#include <iostream>

#include <deque>

#if _MSC_VER > 1020 // if VC++ version is > 4.2

using namespace std; // std c++ libs implemented in std

#endif

int main()

{

deque<int> myDeque(10,1);

int x=0;

deque<int>::iterator iter;

for(iter=myDeque.begin(); iter!=myDeque.end();iter++)

{ cout<<"Element "<<x++<<":"<<*iter<<endl;}

return 1;

}

////////////////////deque赋值///////////////////////////

#include <iostream>

#include <deque>

#if _MSC_VER > 1020 // if VC++ version is > 4.2

using namespace std; // std c++ libs implemented in std

#endif

typedef deque<int, allocator<int> > INTDEQUE;

void printcontents (INTDEQUE deque);

void main()

{

INTDEQUE dequetest;

dequetest.push_front(1);

dequetest.push_front(2);

dequetest.push_front(3);

printcontents (dequetest);

dequetest.pop_front();

printcontents (dequetest);

dequetest.pop_back();

printcontents (dequetest);

}

void printcontents (INTDEQUE deque)

{

INTDEQUE::iterator pdeque;

cout <<"The output is:"<<endl;

for(pdeque = deque.begin(); pdeque != deque.end(); pdeque++)

{ cout << *pdeque <<" " ; };

cout <<endl;

}

//////////////////////////////////内容交换，有两种交换方式，看下面实例//////////////////////////////////

#include <deque>

#include <iostream>

#if _MSC_VER > 1020 // if VC++ version is > 4.2

using namespace std; // std c++ libs implemented in std

#endif

int main( )

{

deque <int> c1, c2, c3;

deque <int>::iterator c1_Iter;

c1.push_back( 1 );

c1.push_back( 2 );

c1.push_back( 3 );

c2.push_back( 10 );

c2.push_back( 20 );

c3.push_back( 100 );

cout << "The original deque c1 is: ";

for ( c1_Iter = c1.begin( ); c1_Iter != c1.end( ); c1_Iter++ )

cout << *c1_Iter << " ";

cout << endl;

c1.swap( c2 ); // 把c1和 c2两个容器中的内容进行相互交换,这是其中一种交换方法，swap当私有变量

cout << "After swapping with c2, deque c1 is: ";

for ( c1_Iter = c1.begin( ); c1_Iter != c1.end( ); c1_Iter++ )

cout << *c1_Iter << " ";

cout << endl;

swap( c1,c3 ); // 把c1和 c3两个容器中的内容进行相互交换，另一种交换方法，swap当通用算法

cout << "After swapping with c3, deque c1 is: ";

for ( c1_Iter = c1.begin( ); c1_Iter != c1.end( ); c1_Iter++ )

cout << *c1_Iter << " ";

cout << endl;

return 0;

}

//////////////////////通过重置assign也可以实现内同交换//////////////////////////

#include <iostream>

#include <deque>

#if _MSC_VER > 1020 // if VC++ version is > 4.2

using namespace std; // std c++ libs implemented in std

#endif

typedef deque<char > CHARDEQUE;

void print_contents (CHARDEQUE deque, char*);

int main()

{

CHARDEQUE a(3,'A'); //定义了变量a,内容是3个'A'

CHARDEQUE b(4,'B'); //定义了变量b,内容是4个'B'

//print_contents (a,"a");

// print_contents (b,"b");

a.swap(b); //内容互换

// print_contents (a,"a");

// print_contents (b,"b");

a.swap(b);//内容换回来

print_contents (a,"a");

print_contents (b,"b");

a.assign(b.begin(),b.end());

print_contents (a,"a");

a.assign(b.begin(),b.begin()+2);

print_contents (a,"a");

a.assign(3,'Z');

print_contents (a,"a");

return 0;

}

//下面是显示函数源代码

void print_contents (CHARDEQUE deque, char *name)

{

CHARDEQUE::iterator pdeque;

cout <<"The contents of "<< name <<" : ";

for(pdeque = deque.begin();

pdeque != deque.end();

pdeque++)

{

cout << *pdeque <<" " ;

}

cout<<endl;

}

///////////////////////////////////////////////////////////插入insert操作，有三种方式/////////////////////////////////////////////////////////////////

#include <iostream>

#include <deque>

#if _MSC_VER > 1020 // if VC++ version is > 4.2

using namespace std; // std c++ libs implemented in std

#endif

typedef deque<char* > CHARDEQUE;

void print_contents (CHARDEQUE deque);

int main()

{ CHARDEQUE a(3,"A");

CHARDEQUE b(2,"B");

print_contents (a);

print_contents (b);

a.insert(a.begin(),"X"); // 在deque的头部插入一元素，值为'X'，第一种方式

print_contents (a);

a.insert(a.end(),"Rlong"); // 在deque的尾部插入一元素，值为'Y'

print_contents (a);

//inset 3 'Z's to one item before the end of a

a.insert(a.end()-1,3,"Z"); // 在deque的尾部前一元素处插入3个元素，值为'Z'，第二中方式

print_contents (a);

a.insert(a.end(),b.begin(),b.end()); // 把b的所有值插入到a变量的尾部，第三种方式

print_contents (a);

return 0;

}

//deque的显示函数

void print_contents (CHARDEQUE deque)

{ CHARDEQUE::iterator pdeque;

cout <<"The output is: ";

for(pdeque = deque.begin(); pdeque != deque.end(); pdeque++)

{ cout << *pdeque <<" " ; }

cout<<endl;

}

///////////////////////////////////erase的两种方式///////////////////////////////////////

#include <deque>

#include <iostream>

#if _MSC_VER > 1020 // if VC++ version is > 4.2

using namespace std; // std c++ libs implemented in std

#endif

int main( )

{ using namespace std;

deque <int> c1;

deque <int>::iterator Iter;

c1.push_back( 10 );

c1.push_back( 20 );

c1.push_back( 30 );

c1.push_back( 40 );

c1.push_back( 50 );

cout << "The initial deque is: ";

for ( Iter = c1.begin( ); Iter != c1.end( ); Iter++ )

cout << *Iter << " ";

cout << endl;

c1.erase( c1.begin( ) ); //第一种方式

cout << "After erasing the first element, the deque becomes: ";

for ( Iter = c1.begin( ); Iter != c1.end( ); Iter++ )

cout << *Iter << " ";

cout << endl;

Iter = c1.begin( );

Iter++;

c1.erase( Iter, c1.end( ) ); //第二种方式

cout << "After erasing all elements but the first, deque becomes: ";

for ( Iter = c1.begin( ); Iter != c1.end( ); Iter++ )

cout << *Iter << " ";

cout << endl;

return 0;

}

//////////////////////////////////////////////////////////////////////

除了可以用erase删除某一特定元素或者某一个范围的元素外，STL还提供了另外一个函数clear，它的功能完全可以被erase替换，等效与erase(deque::begin(),deque::end())

如果deque存储的是类对象，这时一般不能采用clear()函数，因为clear()不会自动释放原来对象元素所占用的内存。这时可以使用erase或者pop_back()辅助delete语句进行内存释放和元素删除操作。

#include <deque>

#include <iostream>

#if _MSC_VER > 1020 // if VC++ version is > 4.2

using namespace std; // std c++ libs implemented in std

#endif

int main( )

{ using namespace std;

deque <int> c1;

c1.push_back( 10 );

c1.push_back( 20 );

c1.push_back( 30 );

cout << "The size of the deque is initially " << c1.size( ) << endl;

c1.clear();

cout << "The size of the deque after clearing is " << c1.size( ) << endl;

return 0;

}