题解 | #牛牛的digit#

思路：将输入的x模上10在除以10，然后依次摘出最后一位数

int main(){
    int x = 0;
    int i = 0;
    scanf("%d %d", &x, &i);
    int ret = 0;
    int mul = 1;
    int each = 0;
    while(i){
        each = (x % 10) * mul;
        mul *= 10;
        ret += each;
        x /= 10;
        i--;
    }
    printf("%d",ret);
    return 0;
}