View Compilation Error

0_0_15778008_630.cpp: In function 'int main()':
0_0_15778008_630.cpp:5:34: error: 'scanf' was not declared in this scope
  scanf("%f%f%f%f",&x1,&y1,&x2,&y2);
                                  ^
0_0_15778008_630.cpp:8:31: error: 'printf' was not declared in this scope
  printf("(d1=%f,(d2=%f)",d1,d2);
                               ^