本人方法比较拙劣， 有许多需要改进的地方

更舒服了

#include <bits/stdc++.h> 
using namespace std; 
int w[5]; 
bool ans = 1; 
bool cmp(int a, int b) 
{ 
    return a > b; 
} 
int main() 
{ 
    int n; 
    cin >> n; 
    while (ans) { 
        int a = n / 1000; 
        int b = n / 100 % 10; 
        int c = n / 10 % 10;
         int d = n % 10;
        w[1] = a; 
        w[2] = b; 
        w[3] = c; 
        w[4] = d;
        sort(w + 1, w + 5, cmp); 
        n = 1000 * w[1] + 100 * w[2] + 10 * w[3] + w[4]; 
        a = n / 1000;
        b = n / 100 % 10; 
        c = n / 10 % 10; 
        d = n % 10; 
        cout << n << "-" << 1000 * d + 100 * c + 10 * b + a << "=" << n - 1000 * d - 100 * c - 10 * b - a;
        cout << endl; 
        if (n - 1000 * d - 100 * c - 10 * b - a == 6174) { 
            ans = 0; 
        } 
            n -= (1000 * d + 100 * c + 10 * b + a) ;
    } 
        return 0; 
}