C++流操作之fstream用法介绍

// stdafx.h : include file for standard system include files, 
// or project specific include files that are used frequently, but 
// are changed infrequently 
// 

#pragma once 

#include "targetver.h" 

#include <stdio.h> 
#include <tchar.h> 
//added 
#include <iostream> 
#include <sstream> 
#include <fstream> 
#include <string> 
#include <vector> 
using namespace std; 

// TODO: reference additional headers your program requires here 
readstla.cpp

// readstla.cpp : Defines the entry point for the console application. 
// 

#include "stdafx.h" 

struct facet { 
    float normal[3]; 
    float vertex[3][3]; 
}; 

int _tmain(int argc, _TCHAR* argv[]) 
{ 
    if (argc < 2) { 
        printf("specify an input file!\n"); 
        return 1; 
    } 
    ifstream in(argv[1]); 
    if (!in.is_open()) { 
        printf("fail to open file!\n"); 
        return 1; 
    } 
    //var 
    vector<facet> solid; 
    string line; 
    string word; 
    //check format 
    getline(in, line); 
    if (line.find("solid") != 0) { 
        printf("wrong file format!\n"); 
        in.close(); 
        return 1; 
    } 
    while (getline(in, line)) { 
        if (line.find("facet normal") != string::npos) { 
            facet f; 
            //read normal 
            stringstream ns(line); 
            ns >> word; //eat "facet" 
            ns >> word; //eat "normal" 
            ns >> f.normal[0] >> f.normal[1] >> f.normal[2]; 
            //read vertices 
            getline(in, line); //"outer loop" 
            for (int i = 0; i < 3; i++) { 
                getline(in, line); 
                stringstream vs(line); 
                vs >> word; //eat "vertex" 
                vs >> f.vertex[i][0] >> f.vertex[i][1] >> f.vertex[i][2]; 
            } 
            getline(in, line); //"endloop" 
            getline(in, line); //"endfacet" 
            solid.push_back(f); 
        } 
    } 
    in.close(); 
    //output 
    int cnt = solid.size(); 
    printf("read %d facet\n", cnt); 
    for (int i = 0; i < cnt; i++) { 
        facet& f = solid[i]; 
        printf("\nfacet %d:\nnormal = (%f, %f, %f)\n", \ 
                       i+1, f.normal[0], f.normal[1], f.normal[2]); 
        for (int j = 0; j < 3; j++) { 
            printf("vertex[%d] = (%f, %f, %f)\n", \ 
                              j+1, f.vertex[j][0], f.vertex[j][1], f.vertex[j][2]); 
        } 
    } 
    return 0; 
}

solid cube_corner 
  facet normal 0.0 -1.0 0.0 
    outer loop 
      vertex 0.0 0.0 0.0 
      vertex 1.0 0.0 0.0 
      vertex 0.0 0.0 1.0 
    endloop 
  endfacet 
  facet normal 0.0 0.0 -1.0 
    outer loop 
      vertex 0.0 0.0 0.0 
      vertex 0.0 1.0 0.0 
      vertex 1.0 0.0 0.0 
    endloop 
  endfacet 
  facet normal 0.0 0.0 -1.0 
    outer loop 
      vertex 0.0 0.0 0.0 
      vertex 0.0 0.0 1.0 
      vertex 0.0 1.0 0.0 
    endloop 
  endfacet 
  facet normal 0.577 0.577 0.577 
    outer loop 
      vertex 1.0 0.0 0.0 
      vertex 0.0 1.0 0.0 
      vertex 0.0 0.0 1.0 
    endloop 
  endfacet 
endsolid