C++, working with .cpp?

Question

C++ / C#

#include <string.h>
#include "my_mega_pack_NativeCallsClass.h"

JNIEXPORT jint JNICALL Java_my_mega_pack_NativeCallsClass_printString
(JNIEnv * jenv, jobject jobj, jstring jstr) {

  const char *string = jenv->GetStringUTFChars(jstr, 0);
  const int size = (unsigned)strlen(string);
  printf("Первый в Dll \n");
  jenv->ReleaseStringUTFChars(jstr, string);
  return size;
};


JNIEXPORT void JNICALL Java_my_mega_pack_NativeCallsClass_printOne
(JNIEnv *jenv, jobject jobj){
  printf("DLL => You are called PrintOne \n");

};


JNIEXPORT void JNICALL Java_my_mega_pack_NativeCallsClass_printTwo
(JNIEnv * jenv, jobject jobj, jint num) {
  printf("DLL => You are called PrintTwo with input param: %d\n ", num);
};

This is a file, and I compile the .h file into a Dll library, and after I work with it in Java code, the question is, can I call other c++ classes written by me from the code above, if so, will they compile are they in Dll too?