初学C#斐波那契三解

#include <stdio.h>int fib_rec( int n ){if(n==0||n==1)return 1;else return fib_rec(n-1)+fib_rec(n-2);}int fib_iter( int n ){int i=2;int num=0;if(n<2)return 1;int head=1,hair=1;for(;i<=n;i++){num=head+hair;hair=head;head=num;}return num;}int feibo(int n){int i,ret;int *f=new int[n+1];f[0]=1;f[1]=1;for(i=2;i<=n;i++){f[i]=f[i-2]+f[i-1];ret =f[i];}delete[]f;return ret;}int main( void ){int i;for( i = 0; i < 15; i++ ){printf( "fib_rec( %d ) = %d\n", i, fib_rec( i ) );printf( "fib_iter( %d ) = %d\n", i, fib_iter( i ) );printf( "feibo( %d ) = %d\n", i, feibo( i ) );}return 0;}