View Compilation Error

0_0_34509215_9328.cpp:7:12: error: '::main' must return 'int'
 void main (){
            ^
0_0_34509215_9328.cpp: In function 'int main()':
0_0_34509215_9328.cpp:8:18: error: 'sum' was not declared in this scope
     double now=1;sum=0;
                  ^