simple application c++

Hi everyone,
i have a simple question, im not expert with C++ stuff,
the question is, my SW is wearching into a text file for a string, then i need to show that string in a Messagebox, and later i will pass it to FPGA,

the question not related to FPGA, its a simple C++ (i think), here is my code

while(!srcfile.eof()) //here im looking for the string i want
{
getline (srcfile,line);
int offset;
if ((offset = line.find(first, 0)) != string::npos) {
cout << "found '" << first << "' @ offset " << offset << endl;
break;
}
i++ ; //line number
}
MessageDlg("found at line." + i , 0); //here im trying to show the line number in messagebox, BUT i receive this error

[BCC32 Warning] ScanDirector_Startup.cpp(82): W8012 Comparing signed and unsigned values
[BCC32 Error] ScanDirector_Startup.cpp(91): E2285 Could not find a match for 'MessageDlg(const wchar_t *,int)'

thanks in advance

Well, I guess the question is "Why do you I get and error?"
Your compiler first complains about comparison of unsigned and singed values: Make offset a unsigned value (uint16_t, uint32_t...)
The error seems also quite obvious: Could not find a match for 'MessageDlg(const wchar_t *,int)'
1.) I do not see forward declarations of the function. Include the appropriate header.
2.) make sure you also link (or compile and link) the a library or function body.

I hope that helps.

Best regards
Thomas

Thanks bunch Thomas, the problem solved , it was a library