SAMI MUSHTAQ:t0_string not declare in this scope
hash not declare in this scope
If I try to compile your code using an online C++ compiler: https://www.onlinegdb.com/online_c++_compiler
It finds no compilation errors, indeed it appears to run.
So either you have shown us the wrong code, or you are compiling the wrong code.
We can't help you with either of those!