演習 7-4

#include <stdio.h>

void printbits(unsigned x) {
int i;

for (i = (8 * sizeof(unsigned)) - 1; i >= 0; i--) {
if ((x >> i) & 1) {
putchar('1');
}
else {
putchar('0');
}
}
}

unsigned lrotate(unsigned x, int n) {

int bits = (8 * sizeof(unsigned));

return (n ? (x << n) | (x >> (bits - n)) : x);
}

unsigned set(unsigned x, int pos) {

return (x | lrotate(1U, pos));
}

unsigned reset(unsigned x, int pos) {

return (x & ~lrotate(1U, pos));
}

unsigned inverse(unsigned x, int pos) {

return (x ^ lrotate(1U, pos));
}

int main() {

unsigned x;
int n;

printf("整数を入力して下さい："); scanf("%u", &x);
printf("何ビット目を変更しますか？："); scanf("%d", &n);

printf("元の数："); printbits(x); putchar('\n');
printf("%dビット目を1にした数", n); printbits(set(x, n)); putchar('\n');
printf("%dビット目を0にした数", n); printbits(reset(x, n)); putchar('\n');
printf("%dビット目を反転した数", n); printbits(inverse(x, n)); putchar('\n');

return 0;
}