program flow ...
step 1..(11)->if(true) ((11/2=5)*10+11%2=1) ......>STEP 5. 101*10+1=1011 answer
STEP 2.(11/2=5) ->if(true) (5/2=2)*10+5%2=1)......> STEP 6. 10*10+1=101
STEP 3. (5/2=2)->if(true) (2/2=1)*10+2%2=0) .....> STEP 7. 1*10+0=10
STEP 4. (2/2=1)->if(false) return 1 ......now keep on putting the value...