error C2447: “{”: 缺少函数标题(是否是老式的形式表?)

#include "stdio.h"
double average(double array[10]);
void main()
{
    double score[10]={10,20,10,20,10,20,10,20,10,20},result;
    result=average(score);
    printf("average score is %5.2lf\n",result);

}
double average(double array[10]);//把这里的;删掉就可以了
{
    double result=1;
    int i=0;
    for(;i<10;i++)
    {
        result+=array[i];
    }
    result/=10;
    return result;
}