建议在循环后观察i的值
程序代码：#include<stdio.h>
#include<malloc.h>
#define null 0
#define xian "---------------------------------------------------------------------------\n"
struct student
{
int num;
char name[20];
char sex[10];
int addr;
float yuweng;
float shuxue;
float yingyu;
struct student *next;
};
#define changdu sizeof(struct student)
int n;
struct student*
scan()
{
struct student *p;
p=(struct student *)malloc(changdu);
printf("请输入学生信息:\n");
printf("学号:\n");
scanf("%d",&p->num);
printf("姓名:\n");
scanf("%s",p->name);
printf("性别:\n");
scanf("%s",p->sex);
printf("年龄:\n");
scanf("%s",&p->addr);
printf("语文成绩:\n");
scanf("%f",&p->yuweng);
printf("数学成绩:\n");
scanf("%f",&p->shuxue);
printf("英语成绩:\n");
scanf("%f",&p->yingyu);
return p;
}
//输入学生信息
struct student*
chuangjian()
{
struct student *head,*p1,*p2;
p1=p2=(struct student *)malloc(changdu);
p1=scan();
head=null;
while(p1->num!=0)
{
n++;
if(n==1)
head=p1;
else
p2->next=p1;
p2=p1;
p1=(struct student *)malloc(changdu);
p1=scan();
}
p2->next=null;
return head;
}
//创建链表
void
print(struct student *head)
{
struct student *p;
printf(xian);
printf("|\t\t\t学\t生\t信\t息\t\t\t |\n");
printf(xian);
printf("| 学 号 | 姓 名\t| 性 别 | 年 龄 | 语 文 | 数 学 | 英 语 |\n");
p=head;
while(head!=null)
{
printf(xian);
printf("| %d | %s\t| %s | %d | %5.2f | %5.2f | %5.2f |\n",p->num,p->name,p->sex,p->addr,p->yuweng,p->shuxue,p->yingyu);
p=p->next;
}
printf(xian);
}
//输出学生信息
struct student*
del(struct student *head,int num)
{
struct student *p1,*p2;
if(head==null)
printf("暂时没有学生信息.\n");
p1=head;
while(num!=p1->num&&p1->next!=null)
{
p2=p1;
p1=p1->next;
}
if(num==p1->num)
{
if(p1==head)
head=p1->next;
else
p2->next=p1->next;
printf("删除学号为%d的学生信息\n",num);
}
else
printf("没有这个学生的信息\n");
return head;
}
//删除学生信息
struct student*
insert(struct student *head)
{
char x;
struct student *p0,*p1,*p2;
p1=head;
printf("请问是否要插入学生信息?y或N\n");
scanf("%c",&x);
if(x=='n')
return head;
else
if(x=='y')
{
printf("请输入要插入的学生信息:\n");
p0=(struct student *)malloc(changdu);
printf("学号:\n");
scanf("%d",&p0->num);
printf("姓名:\n");
scanf("%s",p0->name);
printf("性别:\n");
scanf("%s",p0->sex);
printf("年龄:\n");
scanf("%s",&p0->addr);
printf("语文成绩:\n");
scanf("%f",&p0->yuweng);
printf("数学成绩:\n");
scanf("%f",&p0->shuxue);
printf("英语成绩:\n");
scanf("%f",&p0->yingyu);
}
else
{
printf("输入错误,系统会当作您输入的是No\n");
}
if(p0->num>p1->num&&p1->next!=null)
{
p2=p1;
p1=p1->next;
}
if(p0->num<=p1->num)
{
if(head==p1)
head=p0;
else
p2->next=p0;
p0->next=p1;
}
else
{
p1->next=p0;
p0->next=null;
}
return head;
}
//插入学生信息
int
to()
{
int m;
printf("\t1-输入学生信息:\n");
printf("\t2-插入学生信息:\n");
printf("\t3-删除学生信息:\n");
printf("\t4-输出学生信息:\n");
printf("注意:在选2,3,4选项时,先选1进行创建,否则系统错误!!!!\n\n\n\n");
printf("请选择\n");
scanf("%d",&m);
return m;
}
//菜单
void
main()
{
struct student *head;
char b;
int num,m,i=0;
int c;
printf("\t\t************************************************\n");
printf("\t\t* *\n");
printf("\t\t* *\n");
printf("\t\t* 学 生 管 理 系 统 *\n");
printf("\t\t* *\n");
printf("\t\t* *\n");
printf("\t\t* 本系统乃小五制作,版权所有,不可侵犯!!!!!!! *\n");
printf("\t\t************************************************\n\n\n\n\n\n");
for(i=0;i<10;i++)
{
printf("是否进入主菜单?Y或N.\n");
printf("请选择:");
if(i!=0) //add a if
while((c=getchar())!='\n') //add a while
;
scanf("%c",&b); //%s change to %c
while((c=getchar())!='\n') //add a while
;
//printf("%d\n",b);
if(b=='Y'||b=='y')
{
m=to();
switch(m)
{
case 1:
head=chuangjian();
break;
case 2:
head=insert(head);
break;
case 3:
printf("请输入要删除的学生学号:\n");
scanf("%d",&num);
head=del(head,num);
break;
case 4:
print(head);
break;
default:
printf("输入错误\n");
break;
}
}
else
{
printf("\n\n\n\n\t\t****** * * ****** *******\n");
printf("\t\t* * * * * * *\n");
printf("\t\t* * * * * * *\n");
printf("\t\t* * * * * * *\n");
printf("\t\t***** * ***** *******\n");
printf("\t\t* * * * * *\n");
printf("\t\t* * * * * *\n");
printf("\t\t* * * * * *\n");
printf("\t\t****** * ****** *******\n\n\n\n\n\n\n\n\n\n");
printf("谢谢使用!!!\n\n\n\n");
i=10;
}
}
}没有多做测试，不过能解决楼主只能选择一次的问题
