下面通过分别用C和C++来实现一个链栈(链表实现),从中体会数据封装抽象的思想:
C语言实现:
#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
struct Link
{
int data;
struct Link *next;
};
struct Stack
{
struct Link *head;
int size;
};
void StackInit(struct Stack *stack)
{
stack->head = NULL;
stack->size = 0;
}
void StackPush(struct Stack *stack, const int data)
{
struct Link *node;
node = (struct Link *)malloc(sizeof(struct Link));
assert(node != NULL);
node->data = data;
node->next = stack->head;
stack->head = node;
++stack->size;
}
int StackEmpty(struct Stack *stack)
{
return (stack->size == 0);
}
int StackPop(struct Stack *stack, int *data)
{
if (StackEmpty(stack))
{
return 0;
}
struct Link *tmp = stack->head;
*data = stack->head->data;
stack->head = stack->head->next;
free(tmp);
--stack->size;
return 1;
}
void StackCleanup(struct Stack *stack)
{
struct Link *tmp;
while (stack->head)
{
tmp = stack->head;
stack->head = stack->head->next;
free(tmp);
}
stack->size = 0;
}
int main(void)
{
struct Stack stack;
StackInit(&stack);
int i;
for (i = 0; i < 5; i++)
{
StackPush(&stack, i);
}
while (!StackEmpty(&stack))
{
StackPop(&stack, &i);
printf("%d ", i);
}
printf("\n");
return 0;
}
C++实现:
#include <iostream>
using namespace std;
class Stack
{
private:
struct Link
{
int data_;
Link *next_;
Link(int data, Link *next) : data_(data), next_(next)
{
}
};
public:
Stack() : head_(0), size_(0)
{
}
~Stack()
{
Link *tmp;
while (head_)
{
tmp = head_;
head_ = head_->next_;
delete tmp;
}
}
void Push(const int data)
{
Link *node = new Link(data, head_);
head_ = node;
++size_;
}
bool Empty()
{
return (size_ == 0);
}
bool Pop(int &data)
{
if (Empty())
{
return false;
}
Link *tmp = head_;
data = head_->data_;
head_ = head_->next_;
delete tmp;
--size_;
return true;
}
private:
Link *head_;
int size_;
};
// 避免名称冲突
// 类型的扩充
// 数据封装、能够保护内部的数据结构不遭受外界破坏
int main(void)
{
Stack stack; // 抽象数据类型 类类型
int i;
for (i = 0; i < 5; i++)
{
stack.Push(i); // this = &stack
}
while (!stack.Empty())
{
stack.Pop(i);
cout << i << " ";
}
cout << endl;
return 0;
}
输出都是一致的,对比不同的写法,可以体会两种语言的一些不同之处,当然这只是比较显而易见的方面了。
参考:
C++ primer 第四版 Effective C++ 3rd C++编程规范