#include<stdio.h>
int fun(int n); //统计两个数之间的可能路径
int main(void)
{
int a = 0 , b = 0 ;
printf("please input a and b , and a less than b :\n");
scanf("%d",&a);
scanf("%d",&b);
while(a >= b )
{
printf("please input a and b , and a less than b :\n");
scanf("%d",&a);
scanf("%d",&b);
}
int count = fun(b-a); //统计两个数之间的所有可能路径
printf("Possible route is %d\n",fun(b-a));
return 0;
}
int fun(int n)
{
if(n == 1)
{
return 1 ; //如果两个数相差1 ,彼此可能路径只有一条
}
else if(n == 2)
{
return 2; //如果两个数相差2 ,彼此可能路径只有量条
}
else
{
return fun(n-1)+ fun( n-2); // 否则,是其相邻两个数之间的可能路径之和
}
}