程序是这样的：

#include "math.h"
#include "stdio.h"
void main()
{
double a[7000],b[7000];
int i,j;
FILE *ff,*fp;
ff=fp=NULL;
ff=fopen("e:\\er.txt","rb");
fp=fopen("e:\\ez.txt","rb");
i=j=0;

while(!feof(ff))
{
fread(&a[i],sizeof(double),1,ff);
i=i+1;
}
fclose(ff);

while(!feof(fp))
{
fread(&b[j],sizeof(double),1,fp);
j=j+1;
}
fclose(fp);

}


请问为什么单独运行一个while没有问题，而两个同时运行，则运行不了？