Compilare: user.cpp: In function ‘bool sorting(eu2, eu2)’: user.cpp:13:33: warning: suggest parentheses around ‘&&’ within ‘||’ [-Wparentheses] if(a.val>b.val||a.val==b.val&&a.id<b.id) ^ user.cpp: In function ‘int main()’: user.cpp:37:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(p1<v[i].size()||p2<v[j].size()) ^ user.cpp:37:48: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(p1<v[i].size()||p2<v[j].size()) ^ user.cpp:19:28: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("fof.in","r",stdin); ^ user.cpp:20:30: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("fof.out","w",stdout); ^ user.cpp:21:22: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%hd%hd",&n,&m); ^ user.cpp:24:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%hd%hd",&x,&y); ^