从零开始学C++之数据封装与抽象：分别用C和C++来实现一个链栈

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：

C++ Code

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#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：

C++ Code

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#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。