file processing (for file with more than one fields) and problems associated with it

here is a code i wrote to create the symtab of a sic/xe .asm file....

 #include<iostream>
 #include<fstream>
 #include<iomanip>
 #include"aviasm.h"
 using namespace std;

 void aviasm::crsymtab()
{

ofstream ou开发者_JS百科ts("symtab.txt",ios::out);//creating the symtab
ofstream outi("intermfile.txt",ios::out);//creating the intermediate file
ifstream in("asmfile.txt",ios::in);//opening the asmfile which i have already written
in.seekg(0,ios::beg);


char c;
string str[3];
string subset;
long locctr=0;
int i=0;


while((c=in.get())!=EOF)
{
    in.putback(c);
    while((c=in.get())!='\n')
    {
        in.putback(c); //putting back the first encountered letter
        in>>str[i++];  //the asm file has three or less fields in every row
    }

    if(str[0].size()!=0 && str[1].size()!=0 && str[2].size()!=0)//if all 3 are there
    {

        if(str[1]=="start")
        {
            outi<<hex<<locctr;
            outs<<str[1]<<" "<<locctr<<"\n";
            outs<<resetiosflags(ios::hex);
            outi<<" "<<str[0]<<" "<<str[1]<<" "<<str[2]<<"\n";
            locctr=stol(str[2],0,16);
        }//str[1]=start
     }//end of all the three fields
}
in.close();
outi.close();
outs.close();
}//end of crsymtab

.....here is a sample sic/xe .asm file.....note that in the above code i have not included the entire coded because the problem occurs even if i comment out the entire portion of the code except the above...the problem that occurs is whenever i run the code:

1. A message box with: 'Unhandled exception at 0x00ba7046 in aviasm.exe: 0xC0000005: Access violation writing location 0xcccccccc.' appears and my program enters

   debugging mode...also a file named iosfwd(std::char_traits<char>) appears with an arrow at the line _Left=_Right; of the following function:

   static void __CLRCALL_OR_CDECL assign(_Elem& _Left, const _Elem& _Right) { // assign an element _Left = _Right; }

2. Also, I output a few words to the console at the start and end of the block str[1]="start" to check whether this function was working...although both lines were

   working and I am also sure that input is being successfully taken by the program from the asm file(I have checked this),no lines are being output to intermfile and symtab...plz help??

You should run your program inside a debugger. If you are using Windows, then MSVC provides a debug environment. If you are using Linux, compile your program with -g, and run the gdb debugger: gdb ./myprog. You would immediately discover that on this line:

in>>str[i++];  //the asm file has three or less fields in every row

i has a value of 4, which exceeds the size of the str array.