As Christoph Franck already said: The C51 compiler is _not_ a C++ compiler.

So stop using C++ sources to compile in the C compiler for 8051.

I did not compile that hard readable unformatted code, however what
can be seen immediately by just watching it is:

1) while (1=1)
Can not compile at all, neither in C nor in an C++ compiler

2) for (int word=0; and so on
is C++ not C

3) if (word_count=0)
is most likely wrong.

Just rework your code. Or better start with much smaller real
existing examples for your 8051 compiler, and get them working
first.

Best regards
Juergen