Compilare: user.cpp: In function ‘int main()’: user.cpp:103:19: warning: unused variable ‘k’ [-Wunused-variable] for(int i = 2, k; i <= N; i++) { ^ user.cpp:88:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("center.in", "r", stdin); ^ user.cpp:89:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("center.out", "w", stdout); ^ user.cpp:91:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &N, &L); ^ user.cpp:92:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &W1); ^ user.cpp:93:41: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d %d", &A, &B, &C1, &D); ^