Compilare: user.cpp: In function ‘int main()’: user.cpp:30:28: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf( fin, "%d", &n ); ^ user.cpp:33:50: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf( fin, "%lf%lf", &v[i].x, &v[i].y ); ^ user.cpp:42:22: warning: ‘l’ may be used uninitialized in this function [-Wmaybe-uninitialized] swap( v[l], v[0] ); ^