View Compilation Error

0_0_18140958_11617.cpp: In function 'int main()':
0_0_18140958_11617.cpp:6:22: error: 'scanf' was not declared in this scope
     scanf("%d", &kase);
                      ^
0_0_18140958_11617.cpp:141:65: error: 'printf' was not declared in this scope
             printf("%.1lf\n", nums&1 ? (double)y : x*0.5 + y*0.5);
                                                                 ^