Read / Write INI file

CString cResString;
int value = 0;

// read string
DWORD dwResult = GetPrivateProfileString("section", "key", "return", cResString.GetBuffer(MAX_PATH), MAX_PATH,"Section.ini");

// read integer
value= GetPrivateProfileInt("section", "value", 0, "Section.ini");

// write string
WritePrivateProfileString("section", "key",cResString,"Section.ini");

Section.ini
[section]
key=string
value=100

Ref:
http://support.microsoft.com/kb/90988