View Compilation Error

0_0_25907346_11025.cpp:2:11: error: '::main' must return 'int'
 void main()
           ^
0_0_25907346_11025.cpp: In function 'int main()':
0_0_25907346_11025.cpp:6:25: error: 'scanf_s' was not declared in this scope
  while (scanf_s("%d", &n),n!=0){
                         ^
0_0_25907346_11025.cpp:10:25: error: 'memset' was not declared in this scope
   memset(a, 0, sizeof(a)); 
                         ^
0_0_25907346_11025.cpp:37:5: error: 'cout' was not declared in this scope
     cout << a[i][0] << endl;
     ^
0_0_25907346_11025.cpp:37:24: error: 'endl' was not declared in this scope
     cout << a[i][0] << endl;
                        ^