1's Complement of a Number

#include<stdio.h>
#include<math.h>
#include<conio.h>

 void main()
  {
int n;
scanf("%d",&n);
int bin[20];    // Binary Equivalent Number of 'n'
int k = 0;
int i;
while(n != 0)
{
 bin[k] = n % 2;    // Computing Binary Equivalent Number of 'n' in Reverse Order
 k++;
 n = n/2 ;
}

 printf("\n\n");
for(i=k-1;i>=0;i--)
 printf(" %d",bin[i]);

for(i=0;i<k;i++)
 bin[i] = (bin[i]==1)?0:1;  // Complementing Binary Equivalent Number of 'n'

printf("\n\n");
for(i=k-1;i>=0;i--)
 printf(" %d",bin[i]);

i = 0;
n = 0;
int prod = 1;

while(i<k)
{
 printf(" %d",prod);
 n = n + (bin[i]*prod);               // Computing 'n' from Binary Equivalent Number
 prod *= 2;

 ++i;
}
printf("\n %d",n);

getch();
}