汪涵的说话之道.pdf:c 帮帮忙

如何才能多次输入数据而不覆盖，现在这个程序每次退回主程序在输入数据时都会覆盖掉原数据
#define M 1000

struct stu{
char num[9];
char name[8];
char sex[8];
char acemidy[8];
char type[8];
}stu[M];
create_list()
{ int i;
char cnum[9];
char cname[8];
char csex[8];
char cacemidy[8];
char ctype[8];
for(i=0;i<M;i++)
{ printf("please input 000 to exit.\n");
printf("please input number:");
scanf("%s",cnum);
if(cnum[0]=='0'&&cnum[1]=='0'&&cnum[2]=='0') break;
printf("please input name:");
scanf("%s",cname);
printf("please input sex:");
scanf("%s",csex);
printf("please input acemidy:");
scanf("%s",cacemidy);
printf("please input type:");
scanf("%s",ctype);
strcpy(stu[i].num,cnum);
strcpy(stu[i].name,cname);
strcpy(stu[i].sex,csex);
strcpy(stu[i].acemidy,cacemidy);
strcpy(stu[i].type,ctype);
}
getch();
}
void main()
{color();
for(;;)
{
char key;
printf(" #*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#\n");
printf(" student card program\n");
printf(" #*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#\n");
printf(" exit..........................................0\n");
printf(" input information.............................1\n");
printf(" search information............................2\n");
printf(" modify information............................3\n");
printf(" delete information............................4\n");
scanf("%s",&key);
switch(key){
case '0':
exit(0);
case '1':
create_list();
break;
case '2':
search_students();
break;
case '3':
modify_students();
break;
case '4':
delete_students();
break;
default:
printf("error!\n");
break;
}
}
getch();}