#include <stdio.h> #include <math.h> int main() { int b, c, num = 1000, fan = 0; int a[4] = { 0 }; while (num < 10000) { c = num; for (int i = 0; i < 4; i++) { b = c % 10; c = c / 10; a[i] = b; } fan ...