求助：利用Newton-Raphson法求解平面弹塑性桁架程序错误？？？

zjj820917

利用Newton-Raphson法求解平面弹塑性桁架程序错误如下：
Configuration: xx - Win32 Debug--------------------
Compiling Fortran...
E:\xx\class_4.f90
E:\xx\class_4.f90(24): warning FOR4269: unused dummy argument SUPPORT
E:\xx\class_4.f90(24): warning FOR4269: unused dummy argument GVALUE
E:\xx\class_4.f90(24): warning FOR4269: unused dummy argument LOAD
E:\xx\class_3.f90
E:\xx\class_2.f90
E:\xx\class_2.f90(80): warning FOR4269: unused dummy argument GVALUE
E:\xx\class_2.f90(97): warning FOR4269: unused dummy argument GVALUE
E:\xx\class_2.f90(114): warning FOR4269: unused dummy argument GVALUE
Linking...
libc.lib(wincrt0.obj) : error LNK2001: unresolved external symbol _WinMain@16
Debug/xx.exe : fatal error LNK1120: 1 unresolved externals
Error executing link.exe.
xx.exe - 2 error(s), 6 warning(s)
非常感谢高手的指点！！谢谢

zjj820917

上面发的程序见附件！
感谢各位大侠的帮助！急！！