大一狗。。卡住好久了 看不懂他的错误提示。。VC++6.0

--------------------Configuration: 112 - Win32 Debug--------------------
Compiling...
112.cpp
D:\新建文件夹\Microsoft Visual Studio\MyProjects\112\112.cpp(28) : error C2084: function 'float __cdecl ave(float [])' already has a body
D:\新建文件夹\Microsoft Visual Studio\MyProjects\112\112.cpp(36) : error C2084: function 'float __cdecl sum(float [])' already has a body
执行 cl.exe 时出错.
112.exe - 1 error(s), 0 warning(s)
#include"stdio.h"
float ave(float a[]);
float sum(float a[]);
void main()
{
float a[8];
int i;
printf("请输入八个浮点数，中间用空格分开，按回车结束");
for(i=0;i<=8;i++)
scanf("%f",&a[i]);
printf("和为%f,平均值为%f",sum(a),ave(a));
}
float ave(float a[])
{
int i;
float s;
for(i=0;i<=8;i++)
s+=a[i];
return s/8;
}
float sum(float a[])
{
int i;
float sum;
for(i=0;i<=8;i++)
sum+=a[i];
return sum;
}
刚学函数。。