Undefined Reference errors when using dialog with ncurses

I'm trying to run this code after downloading and installing dialog but run into some undefined reference errors, what am I doing wrong?

I've installed from this link, run ./configure, make, sudo make install, sudo make install-full in the same order and it is successfully installed(no errors printed). In my /usr/local/include I can see dialog.h, dlg_colors.h, dlg_config.h and dlg_keys.h.

When I run g++ -ldialog -lncurses fdialog.cpp I get

 g++ -lncurses -ldialog fdialog.cpp 
/tmp/cc7mK1D2.o: In function `main':
fdialog.cpp:(.text+0x1d): undefined reference to `init_dialog'
fdialog.cpp:(.text+0x3a): undefined reference to `dialog_yesno'
fdialog.cpp:(.text+0x42): undefined reference to `end_dialog'
collect2: error: ld returned 1 exit status