Hamming Number：
m=1^i+2^j+5^k,按此規(guī)律，m=1，2，3，4，5，6，8，9，……，求第n個m

01  #include <iostream>
02  using namespace std;
03  
04  void main(){
05      int n,i;
06      long CountHum = 1, num = 2;
07      i = num;
08  
09  
10      cout<<"Enter the N you want:"<<endl;
11      cin>>n;
12  
13  
14      if (n == 1)
15              cout<<"The Nth number is:1"<<endl;
16      else {
17          while (CountHum < n){
18              while (1){
19                  if (i % 2 == 0)
20                      i = i/2;
21                  if (i % 3 == 0)
22                      i = i/3;
23                  if (i % 5 == 0)
24                      i = i/5;
25                  if (i == 1)
26                      break;
27                  else
28                      if (!((i % 2 == 0) || (i % 3 == 0) || (i % 5 == 0)))
29                          break;
30              }
31  
32  
33              if (i == 1)
34                  CountHum++;
35              num++;
36              i = num;
37          }
38  
39  
40          cout<<"The Nth number is:"<<num-1<<endl;
41      }
42  }