View Compilation Error

0_0_22883997_14602.cpp:3:11: error: '::main' must return 'int'
 void main()
           ^
0_0_22883997_14602.cpp: In function 'int main()':
0_0_22883997_14602.cpp:11:15: error: 's' was not declared in this scope
               s=n*n+n+41;
               ^