boost常用库案例 - [C/C++]

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array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 << " ";
}
}

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 ";
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()));
}