我是初学者，准备写一个磁力数的程序

0999的方法：
cout<<"两者的差值为："<<endl;
char str[256];
char fmt[10];
sprintf(fmt,"%%0%dd",digits);
sprintf(str,fmt,cha);
cout<<str<<endl;

很有意思的题目，如果不用字符串的转换的话，就这样做吧：
#include <iostream>#include <cmath>using namespace std;int Check_Number(int);int Find_Max(int, int);int Find_Min(int, int);int main(){int check = 0;cout<<"Input a number to check:"<<endl;cin>>check;int result = Check_Number(check);cout<<"Result = "<<result<<endl;return 0;}int Check_Number(int test){int n = 0;int max = 0;int min = 0;int diff = -1;int last_time = 0;int temp = test;while(temp){ n++; temp/=10;}while(diff != last_time){ last_time = diff; max = Find_Max(test, n); min = Find_Min(test, n); diff = max - min; test = diff;}return diff;}int Find_Max(int test, int n){int max = 0;int *a = new int[n];int loop = n;while (loop--){ a[loop] = test%10; test/=10;}for(int i = 0; i < n-1; i++){ for(int j = i+1; j < n; j++) { if(a[i] < a[j]) { a[i] = a[i]^a[j]; a[j] = a[i]^a[j]; a[i] = a[i]^a[j]; } }}for(i = 0; i < n; i++){ a[i] = a[i] * (int)pow(10, n-i-1); max += a[i];}//delete [n]a;return max;}int Find_Min(int test, int n){int min = 0;int *a = new int[n];int loop = n;while (loop--){ a[loop] = test%10; test/=10;}for(int i = 0; i < n-1; i++){ for(int j = i+1; j < n; j++) { if(a[i] > a[j]) { a[i] = a[i]^a[j]; a[j] = a[i]^a[j]; a[i] = a[i]^a[j]; } }}for(i = 0; i < n; i++){ a[i] = a[i] * (int)pow(10, n-i-1); min += a[i];}//delete [n]a;return min;}复制代码

对了，记得把上面的代码那个delete [n]a;前面的2个斜线去掉，可以节省内存，刚刚急着写忘记了……[s:468]

谢谢了，我得好好看看。不是一会能看懂的~