Test_C/2.6.txt

#include <stdio.h>

unsigned setbits(unsigned x, int p, int n, unsigned y);
void printfbit(unsigned n);

int main()
{
    printf("76543210\n\n");

    unsigned c1 = 'f';
    printfbit(c1);

    unsigned c2 = 'z';
    printfbit(c2);

    printfbit(setbits(c1, 5, 3, c2));

    return 0;
}

/* setbits: x получает n правых бит из y, начиная с p-й позиции */
unsigned setbits(unsigned x, int p, int n, unsigned y)
{
    return ( (~0 << (p+1)) & x ) | ( ~(~0 << (p+1-n)) & x ) | 
            (~(~0 << n) & y) << (p+1-n);
}

void printfbit(unsigned n)
{
    for(int i = 7; i >= 0; i--)
    {
        if(n & (1 << i))
            putchar('1');
        else
            putchar('0');
    }
    putchar('\n');
}