题解 | #整数与IP地址间的转换#

//无符号左移右移好简洁
#include <stdio.h>

int main() {
    int a,b,c,d;
    unsigned int n1, n2;
    while (scanf("%d.%d.%d.%d", &a, &b, &c, &d) != EOF) {
        scanf("%u", &n1);
        n2 = (a<<24)+(b<<16)+(c<<8)+d;
        printf("%u\n", n2);
        a = (n1>>24);
        b = (n1>>16)&255;
        c = (n1>>8)&255;
        d = n1&255;
        printf("%d.%d.%d.%d\n", a, b, c, d);
    }
    return 0;
}