Compilare: user.cpp: In function ‘int main()’: user.cpp:83:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 1; i < a.size(); i++) { ^ user.cpp:89:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 1; i < b.size(); i++) { ^ user.cpp:95:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 1; i < c.size(); i++) { ^ user.cpp:10:27: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f, "%d %d", &n,&k); ^ user.cpp:29:47: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f, "%d %d %d %d", &x1, &y1, &x2, &y2); ^