aver.obj : error LNK2001: unresolved external symbol "double * ave_stu" (?ave_stu@@3PANA)
aver.obj : error LNK2001: unresolved external symbol "double * ave_cour" (?ave_cour@@3PANA)
LIBCD.lib(wincrt0.obj) : error LNK2001: unresolved external symbol _WinMain@16
Debug/aver.exe : fatal error LNK1120: 3 unresolved externals
代码如下：
#include<stdio.h>
#define N 10
double ave_stu[],ave_cour[];
int stu,cour;
void main()
{
   void aver_stu(float a[][5]);
   void aver_cour(float a[][5]);
   float fangcha( void);
   float a[10][5],c;
   int i,j;
   for(i=0;i<10;i++)
      { printf("\n");
       for(j=0;j<5;j++)
           scanf("%f",&a[i][j]);}

    aver_stu(a);
    aver_cour(a);
    c=fangcha();
    printf("%3f",c);
}

  void aver_stu(float a[][5])
  {
     int i,j;
     float sum_stu[10],max;
  for(i=0;i<10;i++)
     { sum_stu[i]=0;
      for(j=0;j<5;j++)
      {
        sum_stu[i]+=a[i][j];
        ave_stu[i]=sum_stu[i]/5.0;
        if(a[i][j]>max)
        {max=a[i][j];
        stu=i;
        cour=j;}
      }

  }
   for(i=0;i<10;i++)
       printf("%3f ",ave_stu[i]);
  }


    void aver_cour(float a[][5])
    {
     int i,j;
     float sum_cour[5];
      for(j=0;j<5;j++)
      {     sum_cour[i]=0;
              for(i=0;i<10;i++)
              {
               sum_cour[j]+=a[i][j];
        ave_cour[j]=sum_cour[j]/10.0;
              }
      }
      for(i=0;i<5;i++)
          printf("%3f ",ave_cour[i]);
    }

    float fangcha()
    {  
        double sum1,sum2,x;
       int i;
       for(i=0;i<10;i++)
           sum1+=ave_stu[i]*ave_stu[i];
       sum2+=ave_stu[i];
       x=sum1/N-(sum2/N)*(sum2/N);
         
      return(x);
    }

aver.obj : error LNK2001: unresolved external symbol "double * ave_stu" (?ave_stu@@3PANA)        //数组没有定义长度
aver.obj : error LNK2001: unresolved external symbol "double * ave_cour" (?ave_cour@@3PANA)      //数组没有定义长度
LIBCD.lib(wincrt0.obj) : error LNK2001: unresolved external symbol _WinMain@16                   //你建立的是WIN32项目，不能用main()作为入口

非常感谢，已经改过来了