View Compilation Error

0_0_17781107_27673.cpp: In function 'int main()':
0_0_17781107_27673.cpp:16:32: error: 'floor' was not declared in this scope
   case'/':(A / B != floor(A / B)) ? printf("%.2f\n", A / B) : printf("%.0f\n",A/B); break;
                                ^