链表

C语言实现图书管理系统简化版

==可保存的链表==

==双向链表==

图书管理系统（简化版）。

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
struct library{
	char book[40];
	int price;
	struct library *front;
	struct library *next;
};
struct library *first;
struct library *current,*prev,*temp;
FILE *b1,*b2;
void input1();
void input();
void print();
void save();

int main(void)
{
	first=(struct library*)malloc(sizeof(struct library));
	first->next=NULL;
	first->front=NULL;
	input1();
	int n;
	puts("1 input 2 print q break");
	while(scanf("%d",&n)!=0)
	{
		switch(n)
		{
			case 1:input();
				break;
			case 2:print();
				break;
		}
		save();
	}
	
	return 0;
}
//引入链表
void input1()
{
	b1=fopen("book","r");
	b2=fopen("price","r");
	char input[40];
	current=first;
	while(current->next!=NULL)
	{
		prev=current->next;
		current=prev;
	}
	while(fscanf(b1,"%s",input)==1)
	{
		temp=(struct library*)malloc(sizeof(struct library));
		current->next=temp;
		current=current->next;
		strncpy(current->book,input,40);
		fscanf(b2,"%d",&current->price);
		first->front=current;
		current->front=prev;
		current->next=NULL;
		prev=current;
	}
	fclose(b1);
	fclose(b2);
}
//输入链表 
void input()
{
	char input[40];
	current=first;
	while(current->next!=NULL)
	{
		prev=current->next;
		current=prev;
	}
	printf("please enter the book name(enter 0 to quit):");
	while(scanf("%s",input)!=0&&(input[0]!='0'))
	{
		temp=(struct library*)malloc(sizeof(struct library));
		current->next=temp;
		current=current->next;
		strncpy(current->book,input,40);
		printf("please enter the price:");
		scanf("%d",&current->price);
		first->front=current;
		current->front=prev;
		current->next=NULL;
		prev=current;
		printf("please enter the book name(enter 0 to quit):");
	}
	
}
//打印链表 
void print()
{
	current=first->next;
	while(current!=NULL)
	{
		printf("%s:%d\n",current->book,current->price);
		current=current->next;
	}
	current=first->front;
	while(current!=NULL)
	{
		printf("%s:%d\n",current->book,current->price);
		current=current->front;
	}
}
//保存链表
void save()
{
	b1=fopen("book","w");
	b2=fopen("price","w");
	current=first->next;
	while(current!=NULL)
	{
		fprintf(b1,"%s\n",current->book);
		fprintf(b2,"%d\n",&current->price);
		current=current->next;
	}
	fclose(b1);
	fclose(b2);
}

栈

栈的特点是后进先出，这里我们就用数组实现栈。

C++实现

先用结构体定义一个栈

typedef struct {
	ElemType data[maxSize];        //连续内存空间存放栈中元素
	int top;            //存放栈顶元素在data数组中的下标    
}SqStack;

然后初始化栈

void initStack(SqStack& st) {
	st.top = -1;
}

这是进栈函数

int push(SqStack& st, char x) {
	if (st.top == maxSize - 1) {//栈满
		return 0;
	}
	++(st.top);
	st.data[st.top] = x;//先移动指针再进栈
	return 1;
}

这是出栈函数

int pop(SqStack& st, char& x) {
	if (st.top == -1) {
		return 0;
	}
	x = st.data[st.top];
	--(st.top);
	return 1;
}

这个函数判断栈是否为空

int isEmpty(SqStack st) {
	if (st.top == -1) {
		return 1;
	}
	else {
		return 0;
	}
}

这里有两道例题

回文字符串

int main() {
	//回文字符串 
	bool flag=true ;
	char k;
	int i;
	SqStack q;
	initStack(q);
	string s;
	cin>>s;
	int t = s.size();
	for(i = 0 ;i < t/2 ; i++){
		push(q,s[i]);
	}
	if(t%2!=0){
		i++;
	}
	for(i;i<t;i++){
		pop(q,k);
		if(s[i]!=k){
			flag=false;
			break;
		}
	}
	cout<<flag<<endl;
	
	return 0;
}

括号匹配

//括号匹配
int main() {
	int i;
	SqStack q;
	initStack(q);
	string s;
	char r;
	cin>>s;
	int t = s.size();
	for(i=0 ;i<t ; i++){
		if(s[i]=='('||s[i]=='['||s[i]=='{'){
			push(q,s[i]);
		}else{
			pop(q,r);
			if(r!=s[i]){
				break;
			}
		}
	}
	if(isEmpty(q)){
		cout<<"匹配"<<endl;
	}else{
		cout<<"不匹配"<<endl;
	}
	return 0;
}

C语言实现

因为要采用函数封装，结构体能在函数中传递更多参数，所以要定义一个结构体作为主函数与其他函数的桥梁。

栈的结构体

typedef struct Stack {
	ElemType data[maxStack];//栈空间大小为50
	int top;//栈顶位置
}crestack;

初始化栈

crestack* inStack(void) {
	crestack* st;
	st = (crestack*)malloc(sizeof(crestack));
	st->top = -1;

	return st;
}

判断栈是否为空

int isStack(crestack* st) {
	if (st->top == -1) {
		return 1;//1为空
	}
	else
		return 0;//0为不空
}

入栈

int push(crestack* st, char *x) {
	if (st->top == maxStack - 1) {
		return 0;//栈满，入栈失败
	}
	else {
		st->top++;
		st->data[st->top] = *x;
	}
	return 1;
}

出栈

int pop(crestack* st, char *x) {
	if (st->top == -1) {
		return 0;//栈空，出栈失败
	}
	else {
		*x=st->data[st->top];
		st->top--;
	}
	return 1;//出栈成功
}

队列

队列的特点是先进先出。

数组实现队列

因为要采用函数封装，结构体能在函数中传递更多参数，所以要定义一个结构体作为主函数与其他函数的桥梁。

定义一个数组的结构体，用数组做队列，牺牲一个内存空间判断队满，形成环形逻辑。

数组结构体

typedef struct Quere {//数组结构体
	int a[maxquere];
	int end, front,input,output;
}Quere_s;

队列初始化

void enquere(Quere_s* quere) {
	memset(quere->a, 0, 4 * maxquere);
	quere->end = 0;
	quere->front = 0;
}

入队

int inquere(Quere_s* quere, int x) {
	quere->input = x;
	if ((quere->end + 1) % maxquere == quere->front % maxquere && quere->a[quere->front] == 1)
		return 1;//队列已满返回1
	quere->end++;
	quere->a[quere->front % maxquere] = 1;
	quere->a[quere->end % maxquere] = quere->input;

	return 0;//站队成功返回0
}

出队

int outquere(Quere_s* quere) {
	if (quere->end % maxquere == quere->front % maxquere && quere->a[quere->front] == 0)
		return 1;//队列已空返回1
	quere->front++;
	quere->output = quere->a[quere->front % maxquere];
	if (quere->end % maxquere == quere->front % maxquere)
		quere->a[quere->front % maxquere] = 0;
	else
		quere->a[quere->front % maxquere] = 1;

	return 0;//出队成功返回0
}

队列的简单展示

int main(void) {
	//数组实现队列
	Quere_s* quere;
	int i;
	quere = (Quere_s*)malloc(sizeof(Quere_s));
	enquere(quere);
	for (i = 1; i <= 100; i++) {
		if (inquere(quere,i)) {
			printf("队列已满\n");
			break;
		}
	}
	while (!outquere(quere)) {
		printf("%d\n", quere->output);
	}
	free(quere);
	
	return 0;
}

链表实现队列

因为要采用函数封装，结构体能在函数中传递更多参数，所以要定义一个结构体作为主函数与其他函数的桥梁。

两个结构体，第二个结构体是链表的结构体。

牺牲一个节点用来判断是否队满。

结构体

typedef struct lQuere {//链表结构体，功能
	struct LQuere* front, * end;
	int input, output;
}Quere_l;
typedef struct LQuere {//链表结构体,内容
	int a;
	struct LQuere* next;
}LQuEre;

对列初始化

void enquere_l(Quere_l* quere) {
	LQuEre* current;
	int i;
	quere->front = quere->end = (LQuEre*)malloc(sizeof(LQuEre));
	quere->front->a = 0;
	quere->front->next = NULL;
	current = quere->front;
	for (i = 0; i < maxquere - 1; i++) {
		current->next = (LQuEre*)malloc(sizeof(LQuEre));
		current = current->next;
		current->a = 0;
		current->next = NULL;
	}
	current->next = quere->front;
}

入队

int inquere_l(Quere_l* quere, int x) {
	quere->input = x;
	if (quere->end->next == quere->front && quere->front->a == 1)
		return 1;//队列已满返回1
	quere->end = quere->end->next;
	quere->front->a = 1;
	quere->end->a = quere->input;

	return 0;//站队成功返回0
}

出队

int outquere_l(Quere_l* quere) {
	if (quere->end == quere->front && quere->front->a == 0)
		return 1;//队列已空返回1
	quere->front = quere->front->next;
	quere->output = quere->front->a;
	if (quere->end == quere->front)
		quere->front->a = 0;
	else
		quere->front->a = 1;

	return 0;//出队成功返回0
}

对列清空

这里要注意free掉所有的指针

void free_l(Quere_l* quere) {
	LQuEre* current, * prev;
	int i;
	current = quere->front;
	for (i = 0; i < maxquere - 1; i++) {
		prev = current->next;
		free(current);
		current = prev;
	}
	free(current);
	free(quere);
}

队列的简单展示

LQUere* quere;
	int i;
	quere = (LQUere*)malloc(sizeof(LQUere));
	lenquere(quere);
	for (i = 1; i <= 100; i++) {
		if (linquere(quere, i)) {
			printf("队列已满\n");
			break;
		}
	}
	while (!loutquere(quere)) {
		printf("%d\n", quere->output);
	}
	lfree(quere);

	return 0;
❤️ 转载文章请注明出处，谢谢！❤️