c++读csv

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csvparser.h

#ifndef __CSVPARSE_H_2001_06_07__#define __CSVPARSE_H_2001_06_07__#include <string>using namespace std;class CSVParser { private:  string m_sData;  string::size_type m_nPos;  void SkipSpaces(void); public:  CSVParser();  const CSVParser & operator << (const string &sIn);  const CSVParser & operator << (const char *sIn);  CSVParser & operator >> (int &nOut);  CSVParser & operator >> (double &nOut);  CSVParser & operator >> (string &sOut);};#endif

csvparser.cpp

 #pragma once#include "stdafx.h"#include <iostream>#include <cstdlib>#include "csvparser.h"using namespace std;CSVParser::CSVParser(){  m_sData = "";  m_nPos = 0;}void CSVParser::SkipSpaces(void){  while (m_nPos < m_sData.length() && m_sData[m_nPos] == ' ')    m_nPos++;}const CSVParser & CSVParser::operator <<(const string & sIn){  this->m_sData = sIn;  this->m_nPos = 0;  return *this;}const CSVParser & CSVParser::operator <<(const char *sIn){  this->m_sData = sIn;  this->m_nPos = 0;  return *this;}CSVParser & CSVParser::operator >>(int & nOut){  string sTmp = "";  SkipSpaces();  while (m_nPos < m_sData.length() && m_sData[m_nPos] != ',')    sTmp += m_sData[m_nPos++];  m_nPos++; // skip past comma  nOut = atoi(sTmp.c_str());  return *this;}CSVParser & CSVParser::operator >>(double & nOut){  string sTmp = "";  SkipSpaces();  while (m_nPos < m_sData.length() && m_sData[m_nPos] != ',')    sTmp += m_sData[m_nPos++];  m_nPos++; // skip past comma  nOut = atof(sTmp.c_str());  return *this;}CSVParser & CSVParser::operator >>(string & sOut){  bool bQuotes = false;  sOut = "";  SkipSpaces();  // Jump past first " if necessary  if (m_nPos < m_sData.length() && m_sData[m_nPos] == '"') {    bQuotes = true;    m_nPos++;   }    while (m_nPos < m_sData.length()) {    if (!bQuotes && m_sData[m_nPos] == ',')      break;    if (bQuotes && m_sData[m_nPos] == '"') {      if (m_nPos + 1 >= m_sData.length() - 1)        break;      if (m_sData[m_nPos+1] == ',')        break;    }    sOut += m_sData[m_nPos++];  }  // Jump past last " if necessary  if (bQuotes && m_nPos < m_sData.length() && m_sData[m_nPos] == '"')    m_nPos++;   // Jump past , if necessary  if (m_nPos < m_sData.length() && m_sData[m_nPos] == ',')    m_nPos++;   return *this;}

调用方法：

// csv_test.cpp : 定义控制台应用程序的入口点。//#include "stdafx.h"#include <iostream>#include <fstream>#include <string>#include "csvparser.h"using namespace std;int main(void){ifstream infile("sample.csv");string sLine;string sCol1, sCol3, sCol4;double fCol2;int iCol5, iCol6;CSVParser parser;while (!infile.eof()) {getline(infile, sLine); // Get a lineif (sLine == "")continue;parser << sLine; // Feed the line to the parser// Now extract the columns from the lineparser >> sCol1 >> fCol2 >> sCol3;parser >> sCol4 >> iCol5;parser >> iCol6;cout << "Column1: " << sCol1 << endl<< "Column2: " << fCol2 << endl<< "Column3: " << sCol3 << endl<< "Column4: " << sCol4 << endl<< "Column5: " << iCol5 << endl<< "Column6: " << iCol6 << endl<< endl;}infile.close();system("pause");return 0;}

csv文件

sample.csv

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