substring from main string using CString library functions

Question

Copy a substring from main string using CString library functions.

CString  FilterCriteria ="MESSAGE=2 AND READ = 2 AND Instance=\'SMS/MMS\' 
AND Folder=\'inbox\'";
CString  o_filter;

Now, i want to copy Instance=\'SMS/MMS\' AND Folder=\'inbox\' from FilterCriteria to o_filteredFilterCriteria.

Expected result:

o_filter = Instance=\'SMS/MMS\' AND Folder=\'inbox\'.

Program:

int Pos = FilterCriteria.find(instance); 
int First_Pos = FilterCriteria.find("'");
string temp_str = FilterCriteria.substr(First_Pos+1);
string temp_str =FilterCriteria.
int Second_Pos = temp_str.find("'");  

string tempInstance = FilterCriteria.substr(Pos, First_Pos+Second_Pos-
Pos+2);

temp_str = "";

Pos = FilterCriteria.find(folder);// folder position
string Fold_Str = FilterCriteria.substr(Pos);//string after the folder 
First_Pos = Fold_Str.find("'");// first occurence of string
temp_str = Fold_Str.substr(First_Pos+1);// string after '
Second_Pos = temp_str.find("'");// first occurence of ' in string after '
string tempFolder=originalFilterCriteria.substr(Pos, First_Pos+Second_Pos-
Pos+2);

if ( !tempInstance.isEmpty())
{
    o_filter = " AND ";
    o_filter += tempInstance;
}

if (!tempFolder.isEmpty())
{
    o_filter = " AND ";
    o_filter += tempFolder;
}

This code works for string.h library. The same code doesn't work for CString 
functions as CString library doesn't have substr() function. 

Hulsey

You might be looking for CString::Mid – Upkeep

Thanks @IgorTandetnik. This is helpful. – Hulsey

CString::const_iterator Pos = FilterCriteria.find(instance); CString Inst_str = FilterCriteria.getRight(Pos); CString::const_iterator First_Pos = Inst_str.find("'"); CString temp_str = Inst_str.getRight(First_Pos+1); CString::const_iterator Second_Pos = temp_str.find("'"); CString tempInstance = FilterCriteria.getMid(Pos, (UInt32) First_Pos+Second_Pos-Pos+2); (error: cannot convert CString::const_iterator to integer in second argument) temp_str = ""; How to convert CString::const_iterator to integer as getMid() needs second argument as integer. – Hulsey

You must be using some CString class I'm not familiar with. The one I'm familiar with doesn't have a member named getMid, nor find nor getRight. I no longer have any idea what you are talking about. – Upkeep

Answer 1

I have also searched for an equivalence.

A std::string used like this:

stdString.substr(begin, end - begin + 1);

is equivalent to a MFC CString used like this:

mfcString.Mid(begin, end - begin + 1);

//or
mfcString.Right(mfcString.GetLength() - begin).Left(end - begin + 1);

Chihuahua

Answer 2

I guess Find and cut with Mid will do the trick. See the below example for a better understanding.

I have a CString as path = _T("StackOverflow is the best platform for the programmer.") I want the string as "StackOverflow is the best " only. So first I find "platform" then cut the portion.

CString path = _T("StackOverFlow is the best platform for the programmer.");
int pos = path.Find(_T("platform"));
path = path.Mid(0, pos);

// Output:
// path = "StackOverflow is the best "

// or

int length = path.GetLength();
pos = path.Find(_T("platform"));
path = path.Mid(pos, length);

// Output:
// path = "platform for the programmer."

Bojorquez