Compilare: user.cpp: In function ‘int main()’: user.cpp:6:32: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("unuzero.in","r",stdin);freopen("unuzero.out","w",stdout);scanf("%d%d%d",&n,&a,&b);z[0]=1;s[0]=1; ^ user.cpp:6:66: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("unuzero.in","r",stdin);freopen("unuzero.out","w",stdout);scanf("%d%d%d",&n,&a,&b);z[0]=1;s[0]=1; ^ user.cpp:6:91: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] freopen("unuzero.in","r",stdin);freopen("unuzero.out","w",stdout);scanf("%d%d%d",&n,&a,&b);z[0]=1;s[0]=1; ^