I am trying to develop a autocad like software in C/C++. Can any one suggest me how to start it with ?
You mean an application that includes all 3D functions? You would need a 3D graphics API like OpenGL or DirectX.
There are several APIs built over these(at least over OpenGL) that simplifies a lot of things. For eg: OpenSceneGraph.
So, you would basically need a good 3D API.
Yes I need 3D and click event functions . My question is if I install OpenGL or Directx or other API in Windows 7 then does C++ compiler required for AutoCad like Application development ?
>>Yes I need 3D and click event functions
The 3D APIs i mentioned provide the 3D functionality. For user interaction, you would need to use OS specific features. There are cross platform window management tools available too(like glut).
>> if I install OpenGL or Directx or other API in Windows 7
There is a version of OpenGL already present on Windows 7. You can start development with that, but it's deprecated.
>> then does C++ compiler required for AutoCad like Application development
Did you mean what compiler you can use? You can use any good modern compiler like VC++.