Compilare: user.cpp: In function ‘int main()’: user.cpp:45:32: warning: format ‘%Lf’ expects argument of type ‘long double’, but argument 3 has type ‘std::pair<long double, long double>’ [-Wformat=] fprintf(g,"%.10Lf %.10Lf",a); ^ user.cpp:45:32: warning: format ‘%Lf’ expects a matching ‘long double’ argument [-Wformat=] user.cpp:27:22: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f,"%d",&N); ^ user.cpp:29:45: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] {fscanf(f,"%Lf %Lf",&V[i].x,&V[i].y);a.x+=V[i].x;a.y+=V[i].y;} ^