void pointer (void *)

An example of void pointer
#include <iostream>
using namespace std;

class temp
{
    int num;
public:
    temp(){num=10;}
    void * getNum(void){return ((void *) &num);}
    void setNum(void * myNum){int * thisNum=(int *) myNum; num=*thisNum;}
};

int main()
{
    temp A;
    int mainnum= *(int *) A.getNum();
    int * n;
    int i=30;
    n= &i;
    A.setNum((void *) n);
  mainnum= *(int *) A.getNum();
    return 0;
}