Compilare: user.cpp: In function ‘int main()’: user.cpp:38:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0;j<v[i].size();j++){ ^ user.cpp:40:39: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(j==v[i].size()-1) ^ user.cpp:7:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("copii2.in","r",stdin); ^ user.cpp:8:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("copii2.out","w",stdout); ^ user.cpp:11:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&n,&k); ^