View Compilation Error

0_0_34585023_30453.cpp:3:11: error: '::main' must return 'int'
 void main()
           ^
0_0_34585023_30453.cpp: In function 'int main()':
0_0_34585023_30453.cpp:7:39: error: 'scanf_s' was not declared in this scope
     while (~scanf_s("%c%d", &ch, 1, &n))
                                       ^