How can we write codes for Android using C/C++?

Using Android NDK.
http://developer.android.com/tools/sdk/ndk/index.html You can:
1- Hybrid App Java + Write some function in C++ and call them using JNI interface
2- Complete app in C++ With latest NDK, you can create almost all of you activities and stuff like that using C++.
But as per knowledge, for some stuff of Android written in Java, you need make calls to Java layer using JIN layer