#include<conio.h>
#include<iostream.h>
long int dec2bin(long int dec)
{
long int bin=0,val=1;
while(dec>0)
 {
 bin+=(dec%2)*val;
 val*=10;
 dec/=2;
 }
return bin;
}
long int bin2dec(long int bin)
{
long int Digit_Value=1,dec=0;
while(bin>0)
 {
 dec+=(bin%10)*Digit_Value;
 Digit_Value*=2;
 bin/=10;
 }
return dec;
}
void main(void)
{
clrscr();
long int choice;
cout<<"1. Dec2Bin\n";
cout<<"2. Bin2Dec\n";
cout<<endl<<"I Choose: ";
while(choice>2||choice<1)
 {cin>>choice;}
cout<<"Number: ";
long int num;
cin>>num;
if(choice==1)
 {cout<<dec2bin(num);}
else if(choice==2)
 {cout<<bin2dec(num);}
getch();
}