| DEC | BIN |
| -------- | -------- |
| 0 | 0000 |
| 1 |0001|
|2| 0010|
|3|0011|
|4|0100|

n=25

int bin[31]={0},i=-1;
while(n)
{
    bin[i++]=n%2; 
    n=/2 ;
}