View Compilation Error

0_0_33030132_18173.cpp: In function 'int main()':
0_0_33030132_18173.cpp:6:18: error: 'scanf' was not declared in this scope
     scanf("%d",&n);
                  ^
0_0_33030132_18173.cpp:17:15: error: 'puts' was not declared in this scope
         puts(a);
               ^