c++ - 解析字符串数组C++的内容

Question

我读取了一个文件，并将其内容存储到一个字符串数组中。

我需要更改一些数值，由编译器解释为字符。

文件格式为:ABCDE,EFGHIJ KLMNOPQRS,45.58867,122.59750

我进行了搜索和研究，但还没有深入了解任何内容。

如果有人可以告诉我如何做到这一点，我将非常高兴。

而且我不允许使用 strtod；我认为这是一个 C 函数，我的程序只需要严格的 C++。

这是我到目前为止开发的代码:

#include <iostream>
#include <fstream>
#include <string>
#include <vector>
#include <iomanip>
#include <cstdlib>
#include <sstream>


using namespace std;


int main()
{

    string usrFileStr,
    fileStr = "airNames.txt",  // declaring an obj string literal
    sBuffer,
    sLine = "";

    istringstream iStrStrm;

    int lineCount = 1;
    int nStart;


    fstream inFile;                  // declaring a fstream obj
    // cout is the name of the output stream
    cout << "Enter a file: ";
    cin >> usrFileStr;


    inFile.open( usrFileStr.c_str(), ios::in ); 
    // at this point the file is open and we may parse the contents of it


    while ( getline ( inFile, sBuffer ) && !inFile.eof() )
    {
          nStart = -1 ;
          cout << "First Str " << lineCount << " (";
          for ( int x = nStart + 1; x < sBuffer.length(); x++ )
          {
              if ( sBuffer[ x ] == ',' )
              {
                   nStart = x;
                   break;
                   }
              cout << sBuffer[ x ];


          }
          cout << ") ";
          for ( int x = nStart + 1; x < sBuffer.length(); x++ )
          {

              if ( sBuffer[ x ] == ',' )
              {    
                   nStart = x;
                   break;
                   }
              cout << sBuffer[ x ];
          }
          cout << " (Second Str: "; // lattitude loop


          for ( int x = nStart + 1; x < sBuffer.length(); x++ )
          {
              if ( sBuffer[ x ] == ',' )
              {
                   nStart = x;
                   break;
                   }
              cout << sBuffer[ x ];         
          }

          cout << ", Third String: ";
          for ( int x = nStart + 1; x < sBuffer.length(); x++ )
          {
              if ( sBuffer[ x ] == ',' )
              {
                   nStart = x;
                   break;
                   }
              cout << sBuffer[ x ];
          }
          cout << ") \n";
          lineCount++;
    }


    cout << "There are a Total of: " <<  lineCount << " line(s) in the file."
    << endl;


    inFile.clear();           // clear the file of any errors
    inFile.close();  // at this point we are done with the file and may close it

    fgetc( stdin );
    return 0;
}

我试过只读小数点后两位数，但我只读到一个字符。我的第一次尝试是使用 static_cast 但那还差得远。istringstream 变量不会让它的参数成为一个数组。我不知道该怎么办..

Answer 1

std::stringstream

学会爱它。不是 istringstream，因为您想从中获取输出。像这样的东西:

getline ( inFile, sBuffer );
stringstream myStream(sBuffer);
string first, second, third;
char comma;

myStream >> first;  
myStream >> second;
myStream >> third;

float value1, value2;
myStream >> value1;
myStream >> value2;

此外，我建议您检查以确保文件确实打开了。