View Compilation Error

0_0_23100570_27839.cpp: In function 'int main()':
0_0_23100570_27839.cpp:6:20: error: 'scanf' was not declared in this scope
  while(scanf("%s",a))
                    ^
0_0_23100570_27839.cpp:38:5: error: 'cout' was not declared in this scope
     cout<<b[i]<<" ";
     ^
0_0_23100570_27839.cpp:39:4: error: 'cout' was not declared in this scope
    cout<<endl;
    ^
0_0_23100570_27839.cpp:39:10: error: 'endl' was not declared in this scope
    cout<<endl;
          ^
0_0_23100570_27839.cpp:41:8: error: 'cout' was not declared in this scope
   else cout<<a<<endl;
        ^
0_0_23100570_27839.cpp:41:17: error: 'endl' was not declared in this scope
   else cout<<a<<endl;
                 ^