Compilare: user.cpp: In function ‘void comb()’: user.cpp:57:13: warning: unused variable ‘x2’ [-Wunused-variable] int x1, x2, y1, y2; ^ user.cpp:57:21: warning: unused variable ‘y2’ [-Wunused-variable] int x1, x2, y1, y2; ^ user.cpp: In function ‘int main()’: user.cpp:69:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("spion.in", "r", stdin); ^ user.cpp:70:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("spion.out", "w", stdout); ^ user.cpp:72:22: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d\n", &p); ^ user.cpp:73:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%s", s); ^