View Compilation Error

0_0_34558220_11487.cpp: In function 'int main()':
0_0_34558220_11487.cpp:4:20: error: 'scanf' was not declared in this scope
  scanf("%d%d",&a,&b);
                    ^
0_0_34558220_11487.cpp:5:17: error: 'printf' was not declared in this scope
  printf("%d",a+b);
                 ^