سؤال عن عمل تابع في لغة السي

C program to write all the members of an array of strcures to a file using fwrite(). Read the array from the file and display on the screen.

 #include <stdio.h>
 struct s
   { 
 char name[50];
    int height;
 };
   int main(){
     struct s a[5],b[5];   
     FILE *fptr;
    int i;
     fptr=fopen("file.txt","wb");
      for(i=0;i<5;++i)
     {
         fflush(stdin);
        printf("Enter name: ");
        gets(a[i].name);
         printf("Enter height: "); 
      scanf("%d",&a[i].height); 
      }
       fwrite(a,sizeof(a),1,fptr);
        fclose(fptr);
       fptr=fopen("file.txt","rb");
         fread(b,sizeof(b),1,fptr);
          for(i=0;i<5;++i)
            {
             printf("Name: %s\nHeight: %d",b[i].name,b[i].height);
              }
                 fclose(fptr);
                 }