View Compilation Error

0_0_15008303_15515.cpp: In function 'int main()':
0_0_15008303_15515.cpp:9:34: error: 'scanf' was not declared in this scope
     while (scanf("%lf%lf", &x, &y) == 2) {
                                  ^
0_0_15008303_15515.cpp:12:26: error: 'printf' was not declared in this scope
             printf("-1\n");
                          ^
0_0_15008303_15515.cpp:28:27: error: 'printf' was not declared in this scope
         printf("%d\n", cnt);
                           ^