C语言编程入门——综合练习（三）学生管理系统

# include <stdio.h>
# include <malloc.h>
# include <stdlib.h>

typedef struct Student
{
	char name[20];
	char sex;
	int age;
	int score;
	char sid[20];
	struct Student * pNext;
}ST, *PST;

void print(void);  //欢迎界面
void showMenu(void);  //显示菜单
void help(void);  //显示帮助
PST create_list(void);  //创建链表
void traverse_list(const PST);  //遍历输出链表内容，用const常量修饰指针变量防止变量被修改
bool is_empty(PST);  //判断链表是否为空
int length_list(PST);  //计算链表长度
bool append_list(PST);  //追加数据
bool insert_list(PST);  //插入数据
bool delete_list(PST);  //删除数据
ST get_list(PST);  //获取数据
void sort_list(PST);  //对链表数据按成绩降序排序

int main(void)
{
	int val;
	PST pHead = (PST)malloc(sizeof(ST));

	print();
	printf("\n\n\n");

	pHead = create_list();
	traverse_list(pHead);

	while (true)
	{
		showMenu();

		printf("Please to choose you want to do:\n");
		scanf("%d", &val);

		switch (val)
		{
		case 1:
			append_list(pHead);
			break;
		case 2:
			insert_list(pHead);
			break;
		case 3:
			delete_list(pHead);
			break;
		case 4:
			traverse_list(pHead);
			break;
		case 5:
			sort_list(pHead);
			break;
		case 6:
			help();
			break;
		case 7:
			printf("The program will exit soon!\n");
			break;
		default:
			printf("Input error! Please input again!");
		}
		if (7 == val)
			break;
	}

	return 0;
}

void print(void)
{
	printf("\t*************************************************\n");
	printf("\t*************************************************\n");
	printf("\t******                                     ******\n");
	printf("\t***** Welcome to use Student Manage System! *****\n");
	printf("\t******                                     ******\n");
	printf("\t*************************************************\n");
	printf("\t******************************-By LiFeng*********\n");

	return;
}

void showMenu(void)
{
	printf("\t*************************************************\n");
	printf("\t************** 1. add    ************************\n");
	printf("\t************** 2. insert ************************\n");
	printf("\t************** 3. delete ************************\n");
	printf("\t************** 4. show   ************************\n");
	printf("\t************** 5. sort   ************************\n");
	printf("\t************** 6. help   ************************\n");
	printf("\t************** 7. exit   ************************\n");
	printf("\t*************************************************\n");

	return;
}

PST create_list(void)
{
	int i;
	int j = 0;
	int len;
	PST Student;

	PST pHead = (PST)malloc(sizeof(ST));
	if (NULL == pHead)
	{
		printf("The memory is error!\n");
		exit(-1);
	}

	PST pTail = pHead;
	pTail->pNext = NULL;

	printf("Please input the number of students: ");
	scanf("%d", &len);
	printf("Please input the NO.%d Student information!");

	for (i=0; i<len; ++i)			//for循环创建链表
	{
		printf("Please input the NO.%d Student information!");
		printf("Name: ");
		scanf("%s", Student->name[20]);
		printf("Sex: ");
		scanf("%c", &Student->sex);
		printf("Age: ");
		scanf("%d", &Student->age);
		printf("Score: ");
		scanf("%d", &Student->score);
		printf("Sid: ");
		scanf("%s", Student->sid[20]);
		PST pNew = (PST)malloc(sizeof(ST));
		if (NULL == pNew)
		{
			printf("The memory is error!\n");
			exit(-1);
		}
		pNew = Student;
		pTail->pNext = pNew;
		pNew->pNext = NULL;
		pTail = pNew;
	}
	
	return pHead;
}

void treverse_list(const PST pHead)
{
	int i;
	PST p = pHead->pNext;

	if (is_empty(pHead))
	{
		printf("The list is empty!\n");
		exit(1);
	}

	while (NULL == p->pNext)
	{
		printf("The information of NO.%d are\n", i);
		printf("the name is: %s  ", p->name[20]);
		printf("the sex is: %c  ", p->sex);
		printf("the age is: %d  ", p->age);
		printf("the score is: %d  ", p->score);
		printf("the sid is: %s  ", p->sid);
		printf("\n");

		p = p->pNext;
		++i;
	}

	return;
}

bool is_empty(PST pHead)
{
	PST p = pHead->pNext;

	if (NULL == p)
		return true;
	else
		return false;
}

int length_list(PST pHead)
{
	int len;
	PST p = pHead->pNext;

	while(NULL != p)
	{
		++len;
		p = p->pNext;
	}

	return len;
}

bool append_list(PST pHead)
{
	int i;
	int len;
	int pos;
	PST pTail = (PST)malloc(sizeof(ST));
	PST p = pHead;

	printf("Please input the information you want to append:\n");
	printf("Name: ");
	scanf("%s", &pTail->name[20]);
	printf("Sex: ");
	scanf("%c", &pTail->sex);
	printf("Age: ");
	scanf("%d", &pTail->age);
	printf("Score: ");
	scanf("%d", &pTail->score);
	printf("Sid: ");
	scanf("%s", &pTail->sid[20]);

	len = length_list(pHead);

	for (i=0; i<len; ++i)
	{
		p=p->pNext;
	}

	p->pNext = pTail;

	while (p!=NULL && i<pos)
	{
		p = p->pNext;
	}

	return true;
}

bool insert_list(PST pHead)
{
	int i = 0;
	int pos;
	ST temp;
	PST p = pHead;

	printf("Please input the position of the list: pos = ");
	scanf("%d", &pos);
	printf("Please input the information of the student:\n");
	printf("Name: ");
	scanf("%s", &temp.name[20]);
	printf("Sex: ");
	scanf("%c", &temp.sex);
	printf("Age: ");
	scanf("%d", &temp.age);
	printf("Score: ");
	scanf("%d", &temp.score);
	printf("Sid: ");
	scanf("%s", &temp.sid[20]);

	while (p!=NULL && i<pos)
	{
		p = p->pNext;
		++i;
	}

	if (NULL==p || i>pos)
	{
		printf("Error!\n");
		exit(-1);
	}

	PST pNew = (PST)malloc(sizeof(ST));
	*pNew = temp;
	pNew->pNext = p->pNext;
	p->pNext = pNew;

	return true;
}

bool delete_list(PST pHead)
{
	int i = 0;
	int pos;
	PST p = pHead;
	PST q;
	PST pVal = (PST)malloc(sizeof(ST));

	printf("Please input the position of you want to delete: pos = ");
	scanf("%d", &pos);

	while (p!=NULL && i<pos-1)
	{
		p = p->pNext;
		++i;
	}

	if (NULL==p || i>pos-1)
	{
		printf("Error!\n");
		exit(-1);
	}

	*pVal = *p;
	q = p->pNext;
	p->pNext = p->pNext->pNext;
	free(q);

	printf("Delete successfully! The information of you delete:\n");
	printf("Name: %s", pVal->name[20]);
	printf("Sex: %c", pVal->sex);
	printf("Age: %d", pVal->age);
	printf("Score: %d", pVal->score);
	printf("Sid: %s\n", pVal->sid[20]);

	return true;
}

ST get_list(PST pHead)
{
	int i = 0;
	int pos;
	ST stu;
	PST p = pHead->pNext;

	printf("Please input the position of you need: pos = ");
	scanf("%d", &pos);

	if ( is_empty(pHead) )
	{
		printf("The list is empty!\n");
		return stu;
	}

	while (NULL!=p && i<pos)
	{
		p = p->pNext;
		++i;
	}

	if (NULL==p || i>pos)
	{
		printf("Error!\n");
		exit(-1);
	}

	stu = *p;

	return stu;
}

void sort_list(PST pHead)  //冒泡排序法按成绩降序排序
{
	int i, j;
	int len;
	ST temp;
	PST p, q;

	len = length_list(pHead);

	for (i=0, p=pHead; i<len; ++i, p=p->pNext)
	{
		for (j=0, q=pHead->pNext; j<len-i-1; ++j, q=q->pNext)
		{
			if (p->score < q->score)
			{
				temp = *p;
				*p = *q;
				*q = temp;
			}
		}
	}

	return;
}

void help(void)
{
	printf("It is so easy! Do you need help?\n\n");
}