View Compilation Error

0_0_23261350_7722.cpp: In function 'int main()':
0_0_23261350_7722.cpp:3:21: error: 'scanf' was not declared in this scope
  while(scanf("%d",&a)!=0)
                     ^
0_0_23261350_7722.cpp:14:21: error: 'printf' was not declared in this scope
      printf("%d",sum);
                     ^