View Compilation Error

0_0_31494030_16895.cpp: In function 'int main()':
0_0_31494030_16895.cpp:15:75: error: 'scanf' was not declared in this scope
    while(~scanf("%lf%lf%lf%lf%lf%lf%lf%lf",&x1,&y1,&x2,&y2,&x3,&y3,&x4,&y4))
                                                                           ^
0_0_31494030_16895.cpp:26:22: error: 'printf' was not declared in this scope
       printf("0.00\n");
                      ^
0_0_31494030_16895.cpp:34:28: error: 'printf' was not declared in this scope
          printf("%.2lf\n",s);
                            ^