1069. The Black Hole of Numbers (20)

额，输入的可能不是四位数字

<span style="font-size:14px;">//注意这道题的输入可能不是4位数字，比如输入1，能否正确解读为0001#include<iostream>#include<cstdio>#include<algorithm>#include<cstdlib>#include<cstring>using namespace std;void deal(char *c,char*a,char*b){sort(c+0,c+4);strcpy(b,c);reverse(c+0,c+4);strcpy(a,c);//printf("a=%s\n",a);//printf("b=%s\n",b);}void build(char *a,char*b,char*c){int v = 1;int big,small;while(v!=6174 && v !=0){deal(c,a,b);big = atoi(a);small = atoi(b);v = big-small;printf("%04d - %04d = %04d\n",big,small,v);sprintf(c,"%04d",v);}}int main(){int buf;char c[10];char a[10];char b[10];cin>>buf;sprintf(c,"%04d",buf);build(a,b,c);return 0;}</span>