计算第n个斐波那契数

#include <stdio.h>
int feibo(int n)
{
	int a,b,c;
	a=1;
	b=1;
	c=1;
	while(n>2)
	{
		c=a+b;
		a=b;
		b=c;
		n--;
	}
	return c;
}
int main()
{
	int n;
	scanf("%d",&n);
	int ret=feibo(n);
	printf("ret=%d",ret);
	return 0;
 }