第10章，基本数据结构（栈，队列）

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

typedef struct _stack{
int* arr;
int top, size;
}stack;
stack createStack(int size)
{
stack st;
st.arr = (int*)malloc(size*sizeof(int));
st.top = -1;
st.size = size;
return st;
}
int isEmptyStack(stack &s)
{
return s.top == -1;
}
void push(stack &s, int val)
{
if (s.top == s.size - 1){
int *tmp = s.arr;
s.arr = (int*)malloc(2 * s.size*sizeof(int));
memcpy(s.arr, tmp, s.size*sizeof(int));
s.size = s.size * 2;
}
++s.top;
s.arr[s.top] = val;
}
int pop(stack &s)
{
if (isEmptyStack(s)){
printf("stack is empty\n");
exit(-1);
}
--s.top;
return s.arr[s.top + 1];
}

typedef struct _queue{
int *arr;
int tail, head, size;
}queue;
queue createQueue(int size)
{
queue q;
q.tail = q.head = 0;
q.arr = (int*)malloc(size*sizeof(int));
q.size = size;
return q;
}
void enqueue(queue &q, int val)
{
if (q.head == (q.tail + 1) % q.size){
int *tmp = q.arr;
q.arr = (int*)malloc(2 * q.size*sizeof(int));
memcpy(q.arr, tmp, q.size*sizeof(int));
q.size = 2 * q.size;
}
q.arr[q.tail] = val;
q.tail = (q.tail + 1) % q.size;
}
int dequeue(queue &q)
{
if (q.tail == q.head){
printf("queue is empty\n");
exit(-1);
}
int res = q.arr[q.head];
q.head = (q.head + 1) % q.size;
return res;
}

int main()
{
int a[] = { 1, 2, 3, 4, 5, 6, 7 };
stack ss = createStack(5);
for (int i = 0; i < 7; ++i)
push(ss, a[i]);
printf("%d\n", ss.size);
for (int i = 0; i < 7; ++i)
printf("%d\t", pop(ss));
printf("\n");

queue q = createQueue(5);
for (int i = 0; i < 5; ++i)
enqueue(q, a[i]);
dequeue(q); dequeue(q);
enqueue(q, 100); enqueue(q,200);
for (int i = 0; i <6; ++i)
printf("%d\t", dequeue(q));
}