can't seem to find the errors?

[galerecon]

All I am trying to do is write to file. But I keep getting these errors:
1>c:\...\lab1.cpp(7): error C2065: 'ofstream' : undeclared identifier
1>c:\...\lab1.cpp(7): error C2065: 'myWriteFile' : undeclared identifier
1>c:\...\lab1.cpp(7): error C2182: 'process_payroll' : illegal use of type 'void'
1>c:\...\lab1.cpp(7): fatal error C1903: unable to recover from previous error(s); stopping compilation

here is my code:
pastebin.com/vvUbM1GW

Can anyone figure out what is wrong with it?