Error(s):

source_file.cpp: In function ‘int main()’:
source_file.cpp:29:30: error: conflicting declaration ‘std::vector<char> isPrime’
   std::vector<char> isPrime(n);
                              ^
source_file.cpp:28:21: note: previous declaration as ‘std::vector<bool> isPrime’
   std::vector<bool> isPrime(n);
                     ^
source_file.cpp:30:24: error: conflicting declaration ‘std::bitset<1500000ul> isPrime’
   std::bitset<1500000> isPrime;
                        ^
source_file.cpp:28:21: note: previous declaration as ‘std::vector<bool> isPrime’
   std::vector<bool> isPrime(n);
                     ^