Compilare: user.cpp: In function ‘void back4(int, int)’: user.cpp:25:16: warning: unused variable ‘nrvec’ [-Wunused-variable] static int nrvec , i ; ^ user.cpp:25:24: warning: unused variable ‘i’ [-Wunused-variable] static int nrvec , i ; ^ user.cpp: In function ‘int main()’: user.cpp:89:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("count.in","r",stdin); ^ user.cpp:90:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("count.out","w",stdout); ^ user.cpp:92:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&n,&m); ^ user.cpp:95:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&x,&y); ^