STL generate()与generate_n()

generate()

功能:用指定函数对象产生的值去给容器指定范围内元素赋值

 

template<class ForwardIterator, class Generator>
   void generate(
      ForwardIterator _First,
      ForwardIterator _Last,
      Generator _Gen
   );

generate_n()

 

功能:一个函数对象产生的值给一定的范围内指定数目的容器元素赋值

 

template<class OutputIterator, class Diff, class Generator>
   void generate_n(
      OutputIterator _First,
      Diff _Count,
      Generator _Gen
   );

example:

 

 

#include <iostream>
#include <vector>
#include <algorithm>


using namespace std;


class IntSequence
{
private:
    int m_Value;
public:
    IntSequence(int value):m_Value(value){}
    int operator()()
    {
        return m_Value++;
    }
};


int main()
{
    vector<int> IntVec;
    generate_n(back_inserter(IntVec),9,IntSequence(1));
    for(vector<int>::iterator it=IntVec.begin();it!=IntVec.end();++it)
    {
        cout<<*it<<" ";
    }
    cout<<endl;
    generate(++IntVec.begin(),--IntVec.end(),IntSequence(10));
    for(vector<int>::iterator it=IntVec.begin();it!=IntVec.end();++it)
    {
        cout<<*it<<" ";
    }
    cout<<endl;
    return 0;
}

结果:

 

1,2,3,4,5,6,7,8,9

1,10,11,12,13,14,15,16,9