栈结构
栈是一种特殊的线性结构(先进后出)
顺序栈实现
顺序栈的数据结构
#define OK 1
#define ERROR 0
#define MAXSIZE 20 /* 存储空间初始分配量 */
typedef int Status;
typedef int SElemType; /* SElemType类型根据实际情况而定,这里假设为int */
/* 顺序栈结构 */
typedef struct
{
SElemType data[MAXSIZE];
int top; /* 用于栈顶指针 -1代表空栈*/
}SqStack;
顺序栈操作
// 构建一个空栈S
Status InitStack(SqStack *S){
S->top = -1;
return OK;
}
// 将栈置空
Status ClearStack(SqStack *S){
//疑问: 将栈置空,需要将顺序栈的元素都清空吗?
//不需要,只需要修改top标签就可以了.
S->top = -1;
return OK;
}
// 判断顺序栈是否为空;
Status StackEmpty(SqStack S){
if (S.top == -1)
return TRUE;
else
return FALSE;
}
// 返回栈的长度
int StackLength(SqStack S){
return S.top + 1;
}
// 获取栈顶
Status GetTop(SqStack S,SElemType *e){
if (S.top == -1)
return ERROR;
else
*e = S.data[S.top];
return OK;
}
// 插入元素e为新栈顶元素
Status PushData(SqStack *S, SElemType e){
//栈已满
if (S->top == MAXSIZE -1) {
return ERROR;
}
//栈顶指针+1;
S->top ++;
//将新插入的元素赋值给栈顶空间
S->data[S->top] = e;
return OK;
}
// 删除S栈顶元素,并且用e带回
Status Pop(SqStack *S,SElemType *e){
//空栈,则返回error;
if (S->top == -1) {
return ERROR;
}
//将要删除的栈顶元素赋值给e
*e = S->data[S->top];
//栈顶指针--;
S->top--;
return OK;
}
// 从栈底到栈顶依次对栈中的每个元素打印
Status StackTraverse(SqStack S){
int i = 0;
printf("此栈中所有元素");
while (i<=S.top) {
printf("%d ",S.data[i++]);
}
printf("\n");
return OK;
}
// main函数
int main(int argc, const char * argv[]) {
// insert code here...
printf("顺序栈的表示与实现!\n");
SqStack S;
int e;
if (InitStack(&S) == OK) {
for (int j = 1 ; j < 10; j++) {
PushData(&S, j);
}
}
printf("顺序栈中元素为:\n");
StackTraverse(S);
Pop(&S, &e);
printf("弹出栈顶元素为: %d\n",e);
StackTraverse(S);
printf("是否为空栈:%d\n",StackEmpty(S));
GetTop(S, &e);
printf("栈顶元素:%d \n栈长度:%d\n",e,StackLength(S));
ClearStack(&S);
printf("是否已经清空栈 %d, 栈长度为:%d\n",StackEmpty(S),StackLength(S));
return 0;
}
链式栈实现
链式栈数据结构
//栈元素
typedef struct StackNode
{
SElemType data;
struct StackNode *next;
}StackNode,*LinkStackPtr;
//栈结构
typedef struct
{
LinkStackPtr top;
int count;
}LinkStack;
链式栈操作
/* 构造一个空栈S */
Status InitStack(LinkStack *S)
{
S->top=NULL;
S->count=0;
return OK;
}
/* 把链栈S置为空栈 链式栈需手动释放每个节点*/
Status ClearStack(LinkStack *S){
LinkStackPtr p,q;
p = S->top;
while (p) {
q = p;
p = p->next;
free(q);
}
S->count = 0;
return OK;
}
/* 若栈S为空栈,则返回TRUE, 否则返回FALSE*/
Status StackEmpty(LinkStack S){
if (S.count == 0)
return TRUE;
else
return FALSE;
}
/* 返回S的元素个数,即栈的长度*/
int StackLength(LinkStack S){
return S.count;
}
/* 若链栈S不为空,则用e返回栈顶元素,并返回OK ,否则返回ERROR*/
Status GetTop(LinkStack S,SElemType *e){
if(S.top == NULL)
return ERROR;
else
*e = S.top->data;
return OK;
}
/* 插入元素e到链栈S (成为栈顶新元素)*/
Status Push(LinkStack *S, SElemType e){
//创建新结点temp
LinkStackPtr temp = (LinkStackPtr)malloc(sizeof(StackNode));
//赋值
temp->data = e;
//把当前的栈顶元素赋值给新结点的直接后继
temp->next = S->top;
//将新结点temp 赋值给栈顶指针
S->top = temp;
S->count++;
return OK;
}
/* 若栈不为空,则删除S的栈顶元素,用e返回其值. 并返回OK,否则返回ERROR*/
Status Pop(LinkStack *S,SElemType *e){
LinkStackPtr p;
if (StackEmpty(*S)) {
return ERROR;
}
//将栈顶元素赋值给*e
*e = S->top->data;
//将栈顶结点赋值给p,参考图例①
p = S->top;
//使得栈顶指针下移一位, 指向后一结点. 参考图例②
S->top= S->top->next;
//释放p
free(p);
//个数--
S->count--;
return OK;
}
/* 遍历链栈*/
Status StackTraverse(LinkStack S){
LinkStackPtr p;
p = S.top;
while (p) {
printf("%d ",p->data);
p = p->next;
}
printf("\n");
return OK;
}
int main(int argc, const char * argv[]) {
// insert code here...
printf("链栈定义与实现\n");
int j;
LinkStack s;
int e;
if(InitStack(&s)==OK)
for(j=1;j<=10;j++)
Push(&s,j);
printf("栈中元素依次为:");
StackTraverse(s);
Pop(&s,&e);
printf("弹出的栈顶元素 e=%d\n",e);
StackTraverse(s);
printf("栈空否:%d(1:空 0:否)\n",StackEmpty(s));
GetTop(s,&e);
printf("栈顶元素 e=%d 栈的长度为%d\n",e,StackLength(s));
ClearStack(&s);
printf("清空栈后,栈空否:%d(1:空 0:否)\n",StackEmpty(s));
return 0;
}