View Compilation Error

0_0_23266160_25846.cpp: In function 'int main()':
0_0_23266160_25846.cpp:6:15: error: 'scanf' was not declared in this scope
  scanf("%d",&n);
               ^
0_0_23266160_25846.cpp:11:21: error: 'printf' was not declared in this scope
   printf("6%s\n",s+6);
                     ^