Compilare: user.cpp: In function ‘int main()’: user.cpp:12:143: warning: format ‘%ld’ expects argument of type ‘long int’, but argument 5 has type ‘double’ [-Wformat=] printf("%lf %lf %lf %ld %lf %lf %lf %lf\n",(x1+x2)*0.5,(y1+y2)*0.5,(x2+x3)*0.5,(y2+y3)*0.5,(x4+x3)*0.5,(y4+y3)*0.5,(x1+x4)*0.5,(y1+y4)*0.5); ^ user.cpp:7:42: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("paralelogram2.in","r",stdin); ^ user.cpp:8:44: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("paralelogram2.out","w",stdout); ^ user.cpp:9:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&t); ^ user.cpp:11:65: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d %d%d %d%d %d%d",&x1,&y1,&x2,&y2,&x3,&y3,&x4,&y4); ^