stringstream的具体作用稍后来总结，这里分享一个实例，从txt文档中读取数据，并对进行处理。
#include <iostream>
#include <sstream> //stringstream的头文件
#include <fstream>
#include <vector>
#include <string>
using namespace std;void main()
{ifstream fin("d:\\desk\\face detection\\dataset\\train\\trainImageList.txt");ofstream fout("d:\\desk\\face detection\\dataset\\train\\trainImageList1.txt");char p_data[1024] = { 0 };string filename;while (fin.getline(p_data, sizeof(p_data))){vector<double> data;//stringstream resizeData;//resizeData.str(p_data);stringstream resizeData(p_data); //依照空格将数据分段resizeData >> filename; //向filename流中写入值while (resizeData) //数据流输完后就结束{string a;resizeData >> a;data.push_back(atof(a.c_str()));}//data[0] 不变double temp = data[1];data[1] = data[2];data[2] = data[3];data[3] = temp;//使其为一个正方形double w, h;double differenceValue = 0.0;w = data[2] - data[0];h = data[3] - data[1];differenceValue = abs(w - h);if (w > h)data[3] += differenceValue;elsedata[2] += differenceValue;fout << filename << " ";vector<double>::iterator it = data.begin();for (; it != data.end()-1; it++){fout << *it << " ";}fout << endl;}
}
