关于爬楼梯问题的斐波那契数列

 1 // 非递归
 2 #include <iostream>
 3 using namespace std;
 4 int main()
 5 {
 6     int f1=1,f2=2,f3=4,fn;
 7     int n;
 8     cout<<"输入n=";
 9     cin>>n;
10     if(n <= 0)    return -1;
11     else if(n==1)    {cout<<f1; return 0;}    //很有必要复习下if else语句啊
12     else if(n==2)    cout<<f2;
13     else if(n==3)    cout<<f3;
14     else
15     {
16         for(int i=4; i<=n;i++)
17         {
18             fn =f3+f2+f1;
19             f1=f2;
20             f2=f3;
21             f3=fn;     
22         }
23         cout<<fn;
24     }
25     return 0;
26 }

 1 // Note:Your choice is C++ IDE
 2 #include <iostream>
 3 using namespace std;
 4 
 5 long f1 = 1;
 6 long f2 = 2;
 7 long f3 = 4;
 8 long fn = 0;
 9 long fibonacci(int n)
10 {
11     if(n<=0)    return -1;
12     if(n==1)    return 1;
13     if(n==2)    return 2;
14     if(n==3)    return 4;
15   
16     for(int i = 4; i <= n; i++)
17     {
18         fn =f3+f2+f1;
19         f1=f2;
20         f2=f3;
21         f3=fn;     
22     }
23     return fn;
24 }
25 int main()
26 {
27     int n;
28     cout<<"输入n=";
29     cin>>n;
30       cout <<"f("<<n<<")="<<fibonacci(n)<<endl;
31     return 0;
32 }

 1 // Note:Your choice is C++ IDE
 2 #include <iostream>
 3 using namespace std;
 4 
 5 
 6 void hanoi(int n, char a, char b, char c)
 7 {
 8     if(n==1) //一个盘子，直接从a到c
 9         cout<<a<<" to "<<c<<endl;
10     else
11     {
12         hanoi(n-1,a,c,b);//将n-1个盘子从a柱子(借助c)移动到b
13         cout<<a<<" to "<<c<<endl;//最底的盘子从a到c
14         hanoi(n-1,b,a,c);//n-1个盘子到了最终的位置    
15     }
16 }
17 int main()
18 {
19     char a='a',b='b',c='c';
20     int n;
21     cout<<"输入n=";
22     cin>>n; 
23       hanoi(n,a,b,c);
24     return 0;
25 }