boost库的常用组件的使用(1)

boost库: www.boost.org

 

1.   boost::any

 

boost::any是一种通用的数据类型，可以将各种类型包装后统一放入容器内

最重要的它是类型安全的。有点象COM里面的variant.

 

使用方法：

any::type() 返回包装的类型

any_cast可用于any到其他类型的转化

 

#include <boost/any.hpp>

void test_any()

{

     typedef std::vector<boost::any> many;

     many a;

     a.push_back(2);

     a.push_back(string("test"));

 

     for(unsigned int i=0;i<a.size();++i)

     {

          cout<<a[i].type().name()<<endl;

          try

          {

               int result = any_cast<int>(a[i]);

               cout<<result<<endl;

         }

          catch(boost::bad_any_cast & ex)

          {

               cout<<"cast error:"<<ex.what()<<endl;

         }

     }

}

 

2.   boost::array

 

boost::array仅仅是对数组一层薄薄的封装，提供跟各种算法配合的iterator,使用方法很简单

注意：可以使用{}来初始化array,因为boost所有的成员变量都是public的

 

#include <boost/array.hpp>

void test_array()

{

     array<int,10> ai = {1,2,3};

 

     for(size_t i=0;i<ai.size();++i)

     {

          cout<<ai[i]<<endl;

     }

}

 

3.   boost::lexical_cast

lexical_cast用于将字符串转换成各种数字类型(int,float,short etc.)

 

#include <boost/lexical_cast.hpp>

void test_lexical_cast()

{

     int i = boost::lexical_cast<int>("123");

     cout << i << endl;

}

 

4.   boost::format

boost::format是用于替代c里面的sprintf，优点是类型安全，不会因为类型和参数不匹配而导致程序崩溃了

而且还可以重复使用参数

 

#include <boost/format.hpp>

void test_format()

{

     cout << boost::format("writing %1%,  x=%2% : %3%-th try") % "toto" % 40.23 % 50 <<endl;

 

     format f("a=%1%,b=%2%,c=%3%,a=%1%");

     f % "string" % 2 % 10.0;

 

     cout << f.str() << endl;

}

 

5.   boost::tokenizer

boost::tokenizer是用于切割字符串的，类似于Java里面的StringTokenizer。

 

#include <boost/tokenizer.hpp>

void test_tokenizer()

{

     string s("This is  , a ,test!");

     boost::tokenizer<> tok(s);

     for(tokenizer<>::iterator beg=tok.begin(); beg!=tok.end();++beg){

       cout << *beg << "/n";

     }

}

 

 

6.   boost::thread

boost::thread是为了提供跨平台的thread机制。利用boost::function来完成委托。

 

#include <boost/thread.hpp>

void mythread()

{

     cout<<"hello,thread!"<<endl;

}

 

void test_thread()

{

     boost::function< void () > f(mythread);

     boost::thread t(f);

     t.join();

     cout<<"thread is over!"<<endl;

}

 

7.   boost::serialization

boost::serialization提供object的序列化功能。而且提供好几种序列化的格式，比如text,binary,xml

 

#include <boost/archive/text_oarchive.hpp>

#include <boost/archive/text_iarchive.hpp>

#include <boost/archive/xml_oarchive.hpp>

void test_serialization()

{

     boost::archive::text_oarchive to(cout , boost::archive::no_header);

     int i = 10;

     string s = "This is a test/n";

     to & i;

     to & s;

 

     ofstream f("test.xml");

     boost::archive::xml_oarchive xo(f);

     xo & BOOST_SERIALIZATION_NVP(i) & BOOST_SERIALIZATION_NVP(s);

 

     boost::archive::text_iarchive ti(cin , boost::archive::no_header);

     ti & i & s;

     cout <<"i="<< i << endl;

     cout <<"s="<< s << endl;

}

 

8.   boost::function

boost::function就是所谓的泛函数，能够对普通函数指针，成员函数指针，functor进行委托，达到迟调用的效果

 

#include <boost/function.hpp>

int foo(int x,int y)

{

     cout<< "(foo invoking)x = "<<x << " y = "<< y <<endl;

     return x+y;

}

 

struct test

{

     int foo(int x,int y)

     {

          cout<< "(test::foo invoking)x = "<<x << " y = "<< y <<endl;

          return x+y;

     }

};

 

void test_function()

{

     boost::function<int (int,int)> f;

     f = foo;

     cout << "f(2,3)="<<f(2,3)<<endl;

 

     test x;

     /*f = std::bind1st(

      std::mem_fun(&test::foo), &x);*/

     boost::function<int (test*,int,int)> f2;

     f2 = &test::foo;

         

     cout << "f2(5,3)="<<f2(&x,5,3)<<endl;

}

 

9.   boost::shared_ptr

boost::shared_ptr就是智能指针的实现，不象std::auto_ptr，它是可以stl的容器一起使用的，非常的方便

 

#include <boost/shared_ptr.hpp>

class Shared

{

public:

     Shared()

     {

          cout << "ctor() called"<<endl;

     }

     Shared(const Shared & other)

     {

          cout << "copy ctor() called"<<endl;

     }

     ~Shared()

     {

          cout << "dtor() called"<<endl;

     }

     Shared & operator = (const Shared & other)

     {

          cout << "operator =  called"<<endl;

     }

};

 

void test_shared_ptr()

{

     typedef boost::shared_ptr<Shared> SharedSP;

     typedef vector<SharedSP> VShared;

     VShared v;

     v.push_back(SharedSP(new Shared()));

     v.push_back(SharedSP(new Shared()));

}