我用Turbo c/c++ 3.0编如下程序 main() { printf("ni hao ！\n"); } 最后若先用compile进行编译无法link and run ... 提示Function should return a value if I first link but does not compile then I can run please tell me why!!!????? Thanks very much !!!!

若我用Turbo c/c++ 3.0编如下程序 main() { printf("ni hao ！\n"); return 0; } 却很正常!为何要输入return 0????