0

我试图将 int 转换为 string ,但它不起作用我不知道为什么......这是我的代码:

#include <stdio.h>
#include <stdlib.h>  
#include <iostream>
#include <array>


using namespace std;


int main()
{
    struct Studentendaten {
        int matrnr;
        string name;
        string vorname;
        string datum;
        float note;
    };
    Studentendaten stud;
    array<Studentendaten,100> studArray ;   

  FILE * pFile;
  int ch; 
  int mnr;
  string sub;
  string sub1;
  string sub2;
  string sub3;
  string sub4;
  string sub5;

  int i = 0;
  int pos ;

  pFile=fopen("studentendaten.txt","r");  
  if (pFile==nullptr) 
  {
      perror ("Fehler beim öffnen der Datei");
  }
  else
  {       
    while (ch != EOF) 
    {
      ch = fgetc(pFile);
      sub += (char)(ch);
      pos = sub.find(";");
      if (pos != -1) 
      {
          sub1 = sub.substr(0,pos);       
          sub2  = sub.substr(pos+1,pos);
          sub3  = sub.substr(pos+1,pos);
          sub4  =sub.substr(pos+1,pos);
          sub5  =sub.substr(pos+1,pos);       
          mnr   =stoi(sub1);
          stud.matrnr = mnr;
          stud.name = sub2;
          stud.vorname = sub3;
          stud.datum = sub4
          stud.note = float(sub5);
      }
      if (ch == '\n') 
      {
          stud = {matrn,name,vorname,datum,note};
          studArray.[i] = stud;
          i++;
      }


      putchar(ch);
    }   
    fclose (pFile);
    }


  return 0;
}

我试过 int mnr =stoi(sub1); 以及 int mnr = atoi(sub1); 其中 sub1 = "029383214" 类似的东西....为什么它不起作用?编译器抱怨...

4

5 回答 5

2

只需使用std::stringstream

int parse_int( const std::string& str )
{
    std::stringstream ss( str );
    int value;

    if( ss >> value )
        return value;
    else
        throw;
}
于 2013-11-01T14:18:47.373 回答
1

如果我在你的位置,我宁愿使用 boost::lexical_cast

string stringValue = lexical_cast<string>(101);
int intValue = lexical_cast<int>("101");

http://www.boost.org/doc/libs/1_54_0/doc/html/boost_lexical_cast.html

于 2013-11-01T14:10:47.390 回答
1

使用std::to_string(int).

参考。

于 2013-11-01T14:29:08.113 回答
1

您可以使用字符串流:

#include <sstream>
...

// int to string

int intVar = 10;

std::stringstream out;
out << intVar;
std::string converted = out.str();

// string to int

std::string src = "555";
std::stringstream in(str);

int result = 0;
in >> result;

并检查boost::lexical_cast以及。

于 2013-11-01T14:21:17.180 回答
1

您可以std::to_string用于简单的情况或std::stringstream需要对格式进行更多控制(零填充、十六进制等)

#include <iostream>
#include <sstream>
#include <iomanip>

using namespace std;

int main(int argc, const char * argv[]) {
    int value = 19;

    cout << to_string( value ) << endl;

    stringstream s1, s2;
    s1 << setfill('0') << setw(4) << value;
    s2 << "0x" << hex << setfill('0') << setw( 8 ) << value;

    cout << s1.str() << endl << s2.str() << endl;
}
于 2014-03-01T13:31:19.930 回答