Compilare: user.cpp: In function ‘int main()’: user.cpp:70:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("demolish.in", "r", stdin); ^ user.cpp:71:41: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("demolish.out", "w", stdout); ^ user.cpp:73:52: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d %d %d\n", &N, &M, &n, &dx, &dy); ^ user.cpp:77:70: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d %d %d\n", &gr.X1, &Y1, &gr.X2, &Y2, &gr.cost); ^