编译通过 显示乱码
#include<stdio.h>
#include<stdlib.h>
main()
{
 struct stu
 {
  int num;
  char a[10];
  char b;
  int gra;
 }b[4],a[4]={{0,"tom",'m',90},{1,"nancy",'w',78},{2,"mike",'m',23},{3,"jason",'m',89}};
 FILE *fp;
 int n;
  if((fp=fopen("file4","w"))==NULL)
  {
   printf("open error\n");
   exit(0);
  }
  for(n=0;n<4;n++)
   fwrite(&a[n],sizeof(struct stu),1,fp);
  rewind(fp);
  printf("num\tname\tsex\tgrade\n");
  for(n=0;n<4;n++)
  {
   fread(&b[n],sizeof(struct stu),1,fp);
   printf("%d\t%s\t%c\t%d\n",b[n].num,b[n].a,b[n].b,b[n].gra);
  }
  if(fclose(fp))
  {
   printf("close error\n");
   exit(0);
  }
}