Question

I’m havin a problem in including my files. I got 3 C++ files and all of them got int main(void).

THe problem is whenever i include 1 of them it says that:

function ‘int main(void)’ already has a body

but if i will remove the int main(void) to other two C++ file this errors will prompt now.

'one or more multiply defined symbols found'

"class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > __cdecl convertInt(int)" (?convertInt@@YA?AV?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@H@Z) already defined in FormatPosDataXml().obj

"class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > __cdecl convertInt(int)" (?convertInt@@YA?AV?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@H@Z) already defined in FormatPosDataXml().obj    

and so forth

this is the codes that i’ve got:

FormatPosDataXml().cpp

#include <iostream>
#include <sstream>
#include <vector>
#include <string>
#include <cstring>
#include <stdio.h>
#include <conio.h>
#include <stdlib.h>



using namespace std;

#define nextline '\n'

inline bool TextContains(char *text, char ch) {
  while ( *text ) {
    if ( *text++ == ch )
      return true;
  }

  return false;
}

void Split(char *text, char *delims, vector<string> &words) {
  int beg;
  for (int i = 0; text[i]; ++i) {

    while ( text[i] && TextContains(delims, text[i]) )
      ++i;

    beg = i;

    while ( text[i] && !TextContains(delims, text[i]) )
      ++i;
        words.push_back( string(&text[beg], &text[i]) );
  }
}

string convertInt(int number)
{
   stringstream ss;//create a stringstream
   ss << number;//add number to the stream
   return ss.str();//return a string with the contents of the stream
}


string dateFormatChecker(const char *date){
    string strdate=date;
    char getdate[50];
    strcpy_s(getdate, strdate.c_str());

    vector<string> checkdate;
    Split( getdate, "-", checkdate );
    int year, month, day;
    year=atoi(checkdate[0].c_str());
    month=atoi(checkdate[1].c_str());
    day=atoi(checkdate[2].c_str());

    string checkyear, checkmonth, checkday, checkhour, checkminute, checksecond;

            checkyear = convertInt(year);
            if(month<10){
            checkmonth = "0" + convertInt(month);
            }
            else{
            checkmonth = convertInt(month);
            }
            if(day<10){
            checkday = "0" + convertInt(day);
            }
            else{
            checkday = convertInt(day);
            }

            /*
            cout << checkdate[0] << ' ' << checkyear << '\n'
                 << checkdate[1] << ' ' << checkmonth << '\n'
                 << checkdate[2] << ' ' << checkday << '\n';
            */
            if (checkyear.size() != checkdate[0].size()||
                checkmonth.size() != checkdate[1].size()||
                checkday.size() != checkdate[2].size()){
                return "";
            }
    return date;
}

string dateandtimeFormatChecker(const char *dateandtime){
        string strdate=dateandtime;
        char getdateandtime[50];
        strcpy_s(getdateandtime, strdate.c_str());

        vector<string> checkdateandtime;
            Split( getdateandtime, "-: ", checkdateandtime );
        int year, month, day, hour, minute, second;
            year=atoi(checkdateandtime[0].c_str());
            month=atoi(checkdateandtime[1].c_str());
            day=atoi(checkdateandtime[2].c_str());
            hour=atoi(checkdateandtime[3].c_str());
            minute=atoi(checkdateandtime[4].c_str());
            second=atoi(checkdateandtime[5].c_str());

            string checkyear, checkmonth, checkday, checkhour, checkminute, checksecond;

            checkyear = convertInt(year);
            if(month<10){
            checkmonth = "0" + convertInt(month);
            }
            else{
            checkmonth = convertInt(month);
            }
            if(day<10){
            checkday = "0" + convertInt(day);
            }
            else{
            checkday = convertInt(day);
            }
            if(hour<10){
            checkhour = "0" + convertInt(hour);
            }
            else{
            checkhour = convertInt(hour);
            }
            if(minute<10){
            checkminute = "0" + convertInt(minute);
            }
            else{
            checkminute = convertInt(minute);
            }
            if(second<10){
            checksecond = "0" + convertInt(second);
            }
            else{
            checksecond = convertInt(second);
            }


            if (checkyear.size() != checkdateandtime[0].size()||
                checkmonth.size() != checkdateandtime[1].size()||
                checkday.size() != checkdateandtime[2].size()||
                checkhour.size() != checkdateandtime[3].size()||
                checkminute.size() != checkdateandtime[4].size()||
                checksecond.size() != checkdateandtime[5].size()){
                return "";
            }

        //cout << year<< '/' << month << '/' << day << ' ' << hour << ':' << minute << ':' << second << '\n';

        return dateandtime;     
}

string transaction (const char * SequenceNumber, const char * RetailStoreID, const char * WorkStationID, const char * BusinessDayDate, const char * BeginDateTime, const char * StartTransTime, const char * EndTransTime, const char * EndDateTime, const char * RawData){

    string output;

    string bdd, bdt, stt, ett, edt;

    bdd = dateFormatChecker(BusinessDayDate);
    bdt = dateandtimeFormatChecker(BeginDateTime);
    stt = dateandtimeFormatChecker(StartTransTime);
    ett = dateandtimeFormatChecker(EndTransTime);
    edt = dateandtimeFormatChecker(EndDateTime);


    cout << "<Transaction>" << "\n\t<RetailStoreID>"
         << RetailStoreID   << "</RetailStoreID>\n\t<WorkStationID>"
         << WorkStationID   << "</WorkStationID>\n\t<SequenceNumber>"
         << SequenceNumber  << "</SequenceNumber>\n\t<BusinessDayDate>"
         << bdd             << "</BusinessDayDate>\n\t<BeginDateTime>"
         << bdt             << "</BeginDateTime>\n\t<StartTransTime>"
         << stt             << "</StartTransTime>\n\t<EndTransTime>"
         << ett             << "</EndTransTime>\n\t<EndDateTime>"
         << edt             << "</EndDateTime>\n\t<RawData>"
         << RawData         << "</RawData>\n</Transaction>";

    output = _getch();
    return output; 
}

int main(void) {
  vector<string> words;
  char * data = "1,1,SAMPLE,2010-01-31,2011-01-31 14:09:10,2011-01-31 14:42:10,2011-01-31 14:42:10,2011-01-31 14:42:10,JELLY-O RUBBERB\n\r               13.25V.¶üÁËO";

  Split( data, ",", words );

  char SN[11], RSI[200], WSI[200], BDD[100], BDT[100], STT[100], ETT[100], EDT[100], RD[100];

  strcpy_s(SN, words[0].c_str());
  strcpy_s(RSI, words[1].c_str());
  strcpy_s(WSI, words[2].c_str()); 
  strcpy_s(BDD, words[3].c_str());
  strcpy_s(BDT, words[4].c_str());
  strcpy_s(STT, words[5].c_str());
  strcpy_s(ETT, words[6].c_str());
  strcpy_s(EDT, words[7].c_str());
  strcpy_s(RD, words[8].c_str());

  string PosData;
  PosData = transaction(SN,RSI,WSI,BDD,BDT,STT,ETT,EDT,RD);


/* Checker 
  for (int i = 0; i != words.size(); i++){
      cout << words[i] << nextline;
  }
    cout << SN << nextline << RSI << nextline << WSI << nextline << BDD << nextline << BDT << nextline << STT << nextline << ETT << nextline << EDT << nextline << RD; 
*/
return 0;
}

FSNPC.cpp

#include <iostream>
#include <sstream>
#include <vector>
#include <string>
#include <cstring>
#include <stdio.h>
#include <conio.h>
#include <stdlib.h>
#include "FormatPosDataXml().cpp"

using namespace std;


string getstring(string holder){
    if (holder == "" || holder.size()>100){
        exit(1);
    }

    int i=0,ch=0;
    int size;
    char charInput[100];

        strcpy_s(charInput, holder.c_str());
        size = strlen(charInput);

        #define DATA_LENGTH 100
        #define BUFFER_LENGTH (DATA_LENGTH)

        char Buffer[BUFFER_LENGTH];

            while (i < DATA_LENGTH) {
                Buffer[i++] = charInput[i];
                Buffer[i] = '\0';
                if(size == i){
                        break;
                    }
            }
            holder = Buffer;

            strcpy_s(charInput, holder.c_str());
            size = strlen(charInput);

            i = 0;
            for(int j = 0;j<size;j++)
            {
                if (charInput[j] < 2) 
                {
                    if (charInput[j+i] > 2 && charInput[j+i] != 17){
                        charInput[j] = charInput[j+i];
                        charInput[j+i]='\0';
                        i=0;
                        }
                    else{
                        i++;
                        j--;
                    }
                }else if (charInput[j] == 17) 
                {
                    if (charInput[j+i] > 2 && charInput[j+i] != 17){
                        charInput[j] = charInput[j+i];
                        charInput[j+i]='\0';
                        i=0;
                        }
                    else{
                        i++;
                        j--;
                    }
                }
            }
            size = strlen(charInput);
            for(int remove = 0; remove<size ;remove++)
            {
                if (charInput[remove] < 2 || charInput[remove] == 17) 
                {
                    charInput[remove]='\0';
                }
            }

             string handler;
             handler = charInput;

             handler = handler.substr(0, handler.length() - 1);
             return (handler);
    }



/*
int main(void){

    string final;


    string input = "JELLY-O RUBBERB\n\r               13.25V.¶üÁË0";
    string input2 = "STIÁËCK-O CHOCO\n\r               10.52C.ÁË0¶ü";
    string input3 = "STICÁËK-O VANILLA\n\r               10.52C.ÁË0¶ü";


      final = getstring(input)+ "\n" +getstring(input2)+ "\n"
+getstring(input3);
        cout<<final;
        _getch();


    return 0;

}*/

keypress.cpp

#include <iostream>
#include <conio.h>
#include <stdio.h>
#include <string>
#include "FormatPosDataXml().cpp"

    using namespace std;

int c;
char temp[256];

    char getkeypress(char c){

        if (c==0x1b){
            exit(1);
         }

         else if (c==0||c==224)        
          {
                    c = _getch();

                    if (c==0x3b){
                        cout << "You typed: F1\n";
                    }
                    else if(c==0x3c){

                        cout << "You typed: F2\n";
                    }
                    else if(c==0x3d){
                        cout << "You typed: F3\n";
                    }
                    else if(c==0x3e){
                        cout << "You typed: F4\n";
                    }
                    else if(c==0x3f){
                        cout << "You typed: F5\n";
                    }
                    else if(c==0x40){
                        cout << "You typed: F6\n";
                    }
                    else if(c==0x41){
                        cout << "You typed: F7\n";
                    }
                    else if(c==0x42){
                        cout << "You typed: F8\n";
                    }
                    else if(c==0x43){
                        cout << "You typed: F9\n";
                    }
                    else if(c==0x44){
                        cout << "You typed: F10\n";
                    }
                    else if(c==133){
                        cout << "You typed: F11\n";
                    }
                    else if(c==134){
                        cout << "You typed: F12\n";
                    }
          }

          else
          { 
                while((cin.getline(temp, sizeof(temp), '\n'))&&(temp!="")){
                    cout << "You typed:" << temp << '\n';
                    break;
                }
          }

    }
/*  
int main(void){



    while (c^=0x1b){
            cout<<"Press any key:\n";
            c = getkeypress(_getch());
    } 
      _getch();
      return 0;
}
*/

how could I link all of these files. I want them to be a library. How could i do it then?

Answer 1

In general, it is bad practice to include another .cpp file inside of a .cpp file. The right way is to break out declarations into .h files and put the definitions in .cpp files. Make sure to put a bogus define at the top of each of your .h files to prevent accidental re-inclusion, as in:

#ifndef MYFILE_H_
#define MYFILE_H_

// your code goes here

#endif

When you compile your program, you need to compile all the .cpp files into .o files (or .obj on Windows), and then link them together. For example (Linux/Mac):

g++ -c foo.cpp
g++ -c bar.cpp
g++ foo.o bar.o -o theMainExecutable