Reverse the bits in a number

The problem is to reverse the bits in a number.
Example : 1011 should be reversed as 1101

#include <stdio.h>
void bit_form(unsigned int value)
{
            while(value)
            {
                   printf("%d", value & 0x01);
                    value = value >>1;
            }
            printf("\n");
            return;
}
int main()
{
        unsigned int value = 0;
        scanf("%d", &value);
        unsigned int return_value = value;
        int loop = sizeof(value) * CHAR_BIT - 1;

        bit_form(value);

        for(value >>= 1; value; value >>= 1)
        {
                return_value <<= 1;
                return_value |= value & 1;
                loop--;
        }

        return_value <<= loop;
        bit_form(return_value);
        return 0;
}