为什么要用boost::array

为什么要用boost::array

1、boost::array 与 std::vector

( From Chapter 2. Boost.Array)

As replacement for ordinary arrays, the STL provides class std::vector. However, std::vector<>

provides the semantics of dynamic arrays. Thus, it manages data to be able to change the number

of elements. This results in some overhead in case only arrays with static size are needed.

2、便于使用stl中的算法

3、越界检查

尽管抛出assert错误，但总比没有强

4、整体操作数据很方便

boost::array::assign(...)

-----------------------------------------------------------

eg:

#include <iostream>

#include <algorithm>

#include <string>

#include <boost/array.hpp>

template<typename T>

void PrintValue(T value)

{

std::cout<<value<<std::endl;

}

int _tmain(int argc, _TCHAR* argv[])

{

//---------------------------------

//int

boost::array<int, 10> arrInt = {0,1,2}; //未赋值的初试化为0

std::for_each(arrInt.begin(),arrInt.end(),PrintValue<int>);

//所有的值都赋为20

arrInt.assign(20);

std::for_each(arrInt.begin(),arrInt.end(),PrintValue<int>);

//--------------------------------------

//string

boost::array<std::string, 5> arrStr; //默认为""

arrStr.assign("NULL");

std::for_each(arrStr.begin(),arrStr.end(),PrintValue<std::string>);

//越界检查

//std::string strErr = arrStr[5]; //发出assert

//比较

boost::array<std::string, 5> arrStr2;

arrStr2.assign("MULL");

if(arrStr > arrStr2)

std::cout << "arrStr > arrStr2" <<std::endl;

if(arrStr != arrStr2)

std::cout << "arrStr != arrStr2" <<std::endl;

//boost::array<std::string, 6> arrStr3;

//arrStr3.assign("NULL");

//if(arrStr != arrStr3) //无法比较，类型不同5 != 6

// std::cout << "arrStr != arrStr3" <<std::endl;

return 0;

}