严蔚敏关于栈的代码

* 栈基本操作 
* 08/25/2010 
* 参考自严蔚敏等《数据结构(C语言版)》清华大学出版社 
*/ 
#include <iostream> 
#include <stdlib.h> 
#include <assert.h> 
using namespace std; 

// constant definition 
static const int STACK_INIT_SIZE = 10; // the size of initial 
static const int STACK_INCREMENT = 10; // the size of each increase 

// describe the stack 
typedef struct _STACK{ 
int *bottom; 
int *top; 
int size; 
}STACK, *PSTACK; 

// construct an empty stack 
void stack_init(STACK &stack) 
{ 
stack.bottom = (int *) malloc(STACK_INIT_SIZE * sizeof(int)); 
assert(stack.bottom != NULL); 
stack.top = stack.bottom; 
stack.size = STACK_INIT_SIZE; 
} 

// push an element in the stack as the new top 
void stack_push(STACK &stack, int element) 
{ 
if((stack.top - stack.bottom) >= stack.size) 
{ 
// stack is full, allocate more memory 
stack.bottom = (int *) realloc(stack.bottom, (STACK_INIT_SIZE + 
STACK_INCREMENT) * sizeof(int)); 
assert(stack.bottom != NULL); 
stack.top = stack.bottom + stack.size; 
stack.size += STACK_INCREMENT; 
} 

*stack.top++ = element; 
cout << "push " << element << endl; 
} 

// pop the top element in stack if the stack is not empty 
void stack_pop(STACK &stack, int &element) 
{ 
if(stack.top == stack.bottom) 
{ 
// stack is empty, can not pop stack 
cout << "ERROR - pop: stack is empty" << endl; 
return ; 
} 

element = *(--stack.top); 
cout << "pop " << element << endl; 
} 
// get the top element if stack is not empty 
void stack_top(const STACK stack, int &element) 
{ 
if(stack.top == stack.bottom) 
{ 
cout << "ERROR - top: stack is empty" << endl; 
element = -1; 
return; 
} 

element = *(stack.top - 1); 
cout << "top " << element << endl; 
} 

// retrieve the number of elements in stack 
int stack_length(const STACK stack) 
{ 
return (int)(stack.top - stack.bottom); 
} 

// determine whether the stack is empty 
bool stack_is_empty(const STACK stack) 
{ 
return (stack.top - stack.bottom) ? false : true; 
} 
// destroy the stack and the stack is not exist in memory any more 
void stack_destroy(STACK &stack) 
{ 
if(stack.bottom) free(stack.bottom); 
stack.bottom = stack.top = NULL; 
cout << "destroy ok" << endl; 
} 

// clear all elements in stack 
void stack_clear(STACK &stack) 
{ 
stack.top = stack.bottom; 
} 

// traverse the stack and print all elements from top to bottom 
void stack_print(const STACK stack) 
{ if(stack_is_empty(stack)) 
{ 
cout << "stack is empty" << endl; 
return ; 
} 
cout << "(top) "; 
int *p = stack.top; 
while(p != stack.bottom) 
{ 
cout << *(--p) << " "; 
} 
cout << *p << " (bottom)" << endl; 
} 
// start from here 
int main() 
{ 
STACK stack; 
stack_init(stack); 

int i, j; 
for(i=0; i<15; i++) 
stack_push(stack, i); 
stack_print(stack); 
cout << "length " << stack_length(stack) << endl; 
for(j=0; j<16; j++) 
stack_pop(stack, i); 
stack_print(stack); 

if(stack_is_empty(stack)) cout << "stack is empty" << endl; 
else cout << "stack is not empty" << endl; 

stack_clear(stack); 
stack_destroy(stack); 

system("PAUSE"); 
return 0; 
}