View Compilation Error

0_0_25389568_5108.cpp: In function 'int main()':
0_0_25389568_5108.cpp:7:50: error: 'scanf_s' was not declared in this scope
  while (scanf_s("%d %d %d %d", &x1, &y1, &x2, &y2)!=EOF)
                                                  ^
0_0_25389568_5108.cpp:9:53: error: 'sqrt' was not declared in this scope
   m = sqrt((x2 - x1)*(x2 - x1) + (y2 - y1)*(y2 - y1));
                                                     ^