View Compilation Error

0_0_20881930_29919.cpp: In function 'int main()':
0_0_20881930_29919.cpp:8:27: error: 'scanf' was not declared in this scope
     while (~scanf ("%d",&n))  
                           ^
0_0_20881930_29919.cpp:10:17: error: 'getchar' was not declared in this scope
         getchar();  
                 ^
0_0_20881930_29919.cpp:12:9: error: 'stack' was not declared in this scope
         stack<char>s;  
         ^
0_0_20881930_29919.cpp:12:15: error: expected primary-expression before 'char'
         stack<char>s;  
               ^
0_0_20881930_29919.cpp:24:23: error: 's' was not declared in this scope
             else if (!s.empty() && o2[i]==s.top())  
                       ^
0_0_20881930_29919.cpp:43:29: error: 'printf' was not declared in this scope
             printf ("Yes.\n");  
                             ^
0_0_20881930_29919.cpp:55:36: error: 'printf' was not declared in this scope
             printf ("No.\nFINISH\n");  
                                    ^