View Compilation Error

0_0_15974296_24618.cpp: In function 'int main()':
0_0_15974296_24618.cpp:4:27: error: 'scanf' was not declared in this scope
  while (~scanf("%d", &a[0]))
                           ^
0_0_15974296_24618.cpp:24:20: error: 'printf' was not declared in this scope
    printf("%d\n", s);
                    ^