Битовая операция

#include<stdio.h>
void binary(unsigned int x,unsigned int size);
unsigned int check(unsigned int b,unsigned int a);
int main(void)
{
    unsigned int a,b;
    printf("Enter number b (b>0): ");
    scanf("%u",&b);
    printf("Enter bit number a (a<0<=%d): ",8*sizeof(unsigned));
    scanf("%u",&a);
    
    printf("\n");
    printf("Source data\n");
    printf("decimal: %u\n",b);
    printf("heximal: %0*X\n",2*sizeof(unsigned),b);
    printf("binary: ");
    binary(b,8*sizeof(b));
    printf("\n\n\n");
    
    printf("bit number %d has value ",a);
    if(check(b,a))
    printf("1\n\n\n");
    else
    {
    printf("0\n\n\n");
    b=b|(1<<(a-1));
    }
 
    printf("Result\n");
    printf("decimal: %u\n",b);
    printf("heximal: %0*X\n",2*sizeof(unsigned),b);
    printf("binary: ");
    binary(b,8*sizeof(b));
    printf("\n");
    return 0;
}
void binary(unsigned int x,unsigned int size)
{
    if(!size)
    {
        return;
    }
    binary(x/2,--size);
    printf("%u",x%2);
}
unsigned int check(unsigned int b,unsigned int a)
{
    return b&(1<<(a-1));
}