Compilare: user.cpp: In function ‘int main()’: user.cpp:31:9: warning: unused variable ‘i’ [-Wunused-variable] int i, j; ^ user.cpp:31:12: warning: unused variable ‘j’ [-Wunused-variable] int i, j; ^ user.cpp:28:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("ex.in", "r", stdin); ^ user.cpp:29:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("ex.out", "w", stdout); ^ user.cpp:30:34: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d", &n, &k, &p); ^