The introduction of C + + project issues

Iphone project which now need to introduce a few C + + files, code no problem, but the C + + header file, there are several reported errors can not be found, how to solve ah? ? Is not where you want to configure what

For example:
Header file: abc.h
# Include
# Include

Error:
'String' file not found
'Fstream' file not found


Reply:
# Import
The first problem to solve,
The second do not know.
Reply:
. Mm?
Reply:
The Compile source of change obj-c + +
Reply:
3rd floor of this method may be possible, but this will be reported asihttprequest wrong, I still useless this C + + files