View Compilation Error

0_0_17632798_1411.cpp:1:1: error: 'include' does not name a type
 include <stdio.h> 
 ^
0_0_17632798_1411.cpp: In function 'int main()':
0_0_17632798_1411.cpp:6:47: error: 'scanf' was not declared in this scope
  while(scanf("%lf %lf %lf %lf",&x1,&y1,&x2,&y2)!=EOF)
                                               ^
0_0_17632798_1411.cpp:6:50: error: 'EOF' was not declared in this scope
  while(scanf("%lf %lf %lf %lf",&x1,&y1,&x2,&y2)!=EOF)
                                                  ^
0_0_17632798_1411.cpp:9:57: error: 'printf' was not declared in this scope
   printf ("%.2f\n",sqrt((x1-x2)*(x1-x2)+(y1-y2)*(y1-y2)));
                                                         ^