[求助]文件及字符串操作

输入第一个student后，第二个ID被跳过不让输入怎么改？

#include <iostream>
using namespace std;

struct Stu
{
long ID;
int g;
};

int main()
{
char num[20],ch;
struct Stu s;
FILE *fp = fopen("test.txt","wb");
assert(fp != NULL);

do
{
cout << "ID: ";
gets(num);
s.ID = atol(num);

cout << "grades: ";
gets(num);
s.g = atoi(num);

fwrite(&s, sizeof(s), 1, fp);
cout << "another(y/n)?";
ch = getchar();
}while(ch == 'y');

fclose(fp);
}

[此贴子已经被作者于2007-9-14 11:09:17编辑过]