Compilare: user.cpp: In function ‘int main()’: user.cpp:19:41: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("easychoice.in", "r", stdin); ^ user.cpp:20:43: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("easychoice.out", "w", stdout); ^ user.cpp:22:32: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d", &n, &r, &c); ^ user.cpp:23:52: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] for(int i = 1; i <= n ; ++i) scanf("%d", &a[i]); ^