View Compilation Error

0_0_26093343_30753.cpp: In function 'int main()':
0_0_26093343_30753.cpp:3:20: error: 'scanf' was not declared in this scope
  scanf("%d%d",&a,&b);
                    ^
0_0_26093343_30753.cpp:5:17: error: 'printf' was not declared in this scope
  printf("%d",sum);
                 ^