Compilare: user.cpp: In function ‘int main()’: user.cpp:39:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0; j<g1[x1+y1].size(); ++j) ^ user.cpp:55:39: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0; j<g1[x1+y2].size(); ++j) ^ user.cpp:72:39: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0; j<g1[x2+y1].size(); ++j) ^ user.cpp:89:39: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0; j<g1[x2+y2].size(); ++j) ^ user.cpp:13:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("ograzi.in","r",stdin); ^ user.cpp:14:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("ograzi.out","w",stdout); ^ user.cpp:16:34: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d%d",&n,&m,&w,&h); ^ user.cpp:19:40: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&vd[i].x,&vd[i].y); ^ user.cpp:33:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&x,&y); ^