Autometa.... Prove Number is Even

#include<conio.h>
#include<iostream.h>
void main(){
int num;
clrscr();
cout<<"Rule 1:\n 0 € E";
cout<<"Rule 2:\nIf X € E then \n X+2 € E";
cout<<"No Element allowd to be in O if it cant be proved by using above two rules.";
cout<<"Enter number:";
cin>>num;
int step=0;
int k;
if(num%2!=0){
cout<<"Not a Even  number";
 return;}
for(k=0;k<num;k+=2){
  cout<<"Step No. "<<++step<<endl;
  cout<<"Take  X="<<k<<"€ E";
  if(step==1)
  cout<<"Given in rules"<<endl;
cout<<"Proved by step "<<step-1<<endl;
  cout<<"X+2=>"<<k<<"+2"<<"="<<k+2<<endl;
  cout<<"Thus\t"<<k+2<<"€ E"<<endl;
  }
getch();
return ;
}