006 -- Stack_define a stack, push/pop a element to a Stack

000-- Define a Stack

typedef struct{
    ElemType *base;
    ElemType *top;
    int stackSize;
}sqStack;

#define STACK_INIT_SIZE 100

initStack(sqStack *s)
{
s->base = (ElemType *)malloc(STACK_INIT_SIZE*sizeof(ElemType))

if(!s)
{
exit(0);
}

s->top = s->base;
s->stackSize = STACK_INIT_SIZE;

}

001-- Push a data into the Stack

#define STACKINCREMENT 10

Push(sqStack *s, ElemType e)
{
    if(s->top - s->base >= s->stackSize)
    {
        s->base = (ElemType *)realloc(s->base, (s->stackSize + STACKINCREMENT)*sizeof(ElemType));
        if(!s->base)
            exit(0);
        
        s->top = s->base+ s->stackSize; //set the pointer of top 
        s->stackSize = s->stackSize + STACKINCREMENT; //set the current size of the Stack
            
    }
        
    *(s->top) = e;
    s->top++;
            
        
}

002-- pop a data out from Stack

Pop(sqStack *s, ElemType *e)
{
    if(s->top == s->base)
        return;
    
    *e = *--(s->top);
    
}

003--clear a stack

ClearStack(sqStack *s){
s->top = s->base;
}

004--destroy a stack

DestroyStack(sqStack *s)
{
    int i, len;
    len = s->stackSize;
    
    for (i=0;i<len;i++)
    {
        free(s->base);
        s->base ++;
        
    }
    
    s->base = s->top = NULL;
    s->stackSize = 0;
    
}