View Compilation Error

0_0_18851371_13491.cpp:1:2: error: invalid preprocessing directive #lnclude
 #lnclude<math.h>
  ^
0_0_18851371_13491.cpp: In function 'int main()':
0_0_18851371_13491.cpp:5:43: error: 'scanf' was not declared in this scope
  while(scanf("%f %f %f %f",&x1,&x2,&y1,&y2)==4)
                                           ^
0_0_18851371_13491.cpp:6:54: error: 'sqrt' was not declared in this scope
  printf("%.2f\n",sqrt((x1-x2)*(x1-x2)+(y1-y2)*(y1-y2)));
                                                      ^
0_0_18851371_13491.cpp:6:55: error: 'printf' was not declared in this scope
  printf("%.2f\n",sqrt((x1-x2)*(x1-x2)+(y1-y2)*(y1-y2)));
                                                       ^