View Compilation Error

0_0_38034419_12110.cpp: In function 'int main()':
0_0_38034419_12110.cpp:3:27: error: 'scanf' was not declared in this scope
  while(scanf("%d %d",&a,&b)==2){
                           ^
0_0_38034419_12110.cpp:4:20: error: 'printf' was not declared in this scope
   printf("%d\n",a+b);
                    ^