1019. 數字黑洞

include

include

using namespace std;
int big,small;
void xin(int x)
{
int a[4];
a[3]=x%10;
x=x/10;
a[2]=x%10;
x=x/10;
a[1]=x%10;
x=x/10;
a[0]=x%10;
sort(a,a+4);
big=a[3]*1000+a[2]*100+a[1]*10+a[0];
small=a[0]*1000+a[1]*100+a[2]*10+a[3];
}
int main()
{
int n;
cin>>n;
xin(n);
if(big==small)
{
printf(“%04d - %04d = 0000\n”, n, n);
return 0;
}
else
{
int m=big-small;
printf(“%04d - %04d = %04d\n”,big,small,m);
while(m!=6174)
{
xin(m);
m=big-small;
printf(“%04d - %04d = %04d\n”,big,small,m);
}
}
}
這裏學到了兩個地方(“%04d - %04d = %04d\n”,big,small,m);輸出格式爲4位的時候，不足4位補足4位。還有sort函數sort（a,a+4）。4是元素的個數。結果按升序排列