Compilare: user.cpp: In function ‘int main()’: user.cpp:61:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("cowfood.in","r",stdin); ^ user.cpp:62:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("cowfood.out","w",stdout); ^ user.cpp:66:39: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%lld %lld %lld\n",&k,&s,&n); ^ user.cpp:69:49: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] for(j=1;j<=k;j++) scanf("%lld",&a[i][j]); ^