C++保存txt文件实现方法代码实例

#include <windows.h>
#include <fstream>
#include <iostream>
#include <string>
using namespace std;
 
int main()
{
  ifstream myfile("in.txt");
  ofstream outfile("out.txt", ios::app); //ios::app指追加写入
  string temp;
   
  while (getline(myfile, temp)) //按行读取字符串
  {
    outfile << temp<<endl;//写文件
   
  }
  myfile.close();
  outfile.close();
  while (1);
  return 0;
}

#include <iostream>
#include <sstream>
 
using namespace std;
 
int main()
{
  istringstream istr;
  istr.str("1 56.7");
  //上述两个过程可以简单写成 istringstream istr("1 56.7");
  cout << istr.str() << endl;
  int a;
  float b;
  istr >> a;
  cout << a << endl;
  istr >> b;
  cout << b << endl;
  return 0;
}

#include <windows.h>
#include <fstream>
#include <iostream>
#include <string>
 
#include "opencv2/video/tracking.hpp"
#include "opencv2/highgui/highgui.hpp"
 
using namespace std;
using namespace cv;
 
typedef struct TrackingBox
{
  int frame;
  int id;
  Rect_<float> box;
}TrackingBox;
 
 
 
 
/*
1TXT数据存放数据格式
1,-1,281.931,187.466,79.93,209.537,0.997784,-1,-1,-1
1,-1,56.6878,144.225,93.5572,295.907,0.997601,-1,-1,-1
1,-1,378.618,188.922,166.431,234.127,0.995973,-1,-1,-1
1,-1,203.983,207.153,45.553,133.834,0.985409,-1,-1,-1
（抽取单个目标展示）
帧号 目标ID x y w h 准确度
1,-1,291.557,192.468,39.494,119.227,0.995128,-1，-1，-1
 
*/
void TXTtoBOX() {
  string inFileName = "det.txt";
  string outFileName = "out.txt";
 
  ifstream myfile(inFileName);
  ofstream outfile(outFileName, ios::app); //ios::app指追加写入
 
 
  if (!myfile.is_open())
  {
    cerr << "Error: can not find file " << inFileName << endl;
    return;
  }
  if (!outfile.is_open())
  {
    cerr << "Error: can not find file " << outFileName << endl;
    return;
  }
 
  string detLine;//存放读取出的单个目标信息
  istringstream ss;
  vector<TrackingBox> detData;
  char ch;//存放逗号，没有实际用处，去除数据间的逗号
  float tpx, tpy, tpw, tph;
 
  while (getline(myfile, detLine)) //按行读取字符串
  {
    TrackingBox tb;
    ss.str(detLine);
    ss >> tb.frame >> ch >> tb.id >> ch;// ch用来存放逗号
    ss >> tpx >> ch >> tpy >> ch >> tpw >> ch >> tph;
    ss.str("");//清空后面不管
 
    tb.box = Rect_<float>(Point_<float>(tpx, tpy), Point_<float>(tpx + tpw, tpy + tph));
    detData.push_back(tb);
 
    outfile << detLine << endl;//写文件
    cout <<"detLine:"<< detLine << endl;
    cout << "x:"<<tpx << "  y:"<< tpy << " w:" << tpw << " h:" << tph <<endl;
 
  }
  myfile.close();
  outfile.close();
  while (1);
 
 
}
int main()
{
  TXTtoBOX();
   
  return 0;
}