泛性运算问题.cpp

来自「这是一些c++例程」· C++ 代码 · 共 50 行

// 泛性运算问题.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"
#include <iostream>
#include <iterator>
#include <algorithm>
#include <fstream>
#include <string>
#include <functional>
#include <vector>

using namespace std;

int main(void)
{
	cout<<"Please input filename:";
	string filename;
	cin>>filename;			//测试时输入的文件名为:yy.txt,其内容为:
						//6 8 12 23 34 45 56 89 90 109 
	
	if(filename.empty()||!cin){
		cout<<"Can not read filename!\n";
		return -1;
	}
	
	ifstream ff(filename.c_str());
	if(!ff){
		cout<<"Can not open file of "<<filename<<endl;
		return -2;
	}
	
	istream_iterator<int> input(ff);
	istream_iterator<int> end_of_stream;
	
	vector<int> ivec;
	
	copy(input,end_of_stream,inserter(ivec,ivec.begin()));
	
	cout<<ivec[0]<<" "<<ivec[1];	//此处输出结果为6 8
	
	cout<<endl<<endl;
	
	ostream_iterator<int> out(cout," ");
	
	copy(input,end_of_stream,out);	//但是为什么这个地方输出的结果是6,而不是6 8 12 23 34 45 56 89 90 109
	return 0;
}