栈的应用--行编辑器

 

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

#define STACK_INIT_SIZE 10
#define STACKINCREMENT 2

typedef int SElemType;

struct SqStack{
    SElemType *base;
    SElemType *top;
    int stacksize;
};

#define SqStack struct SqStack

int InitStack(SqStack *S)
{    
    if ( !(S->base = (SElemType *) malloc (STACK_INIT_SIZE * sizeof(SElemType))))
        exit(3);
    S->top=S->base;
    S->stacksize=STACK_INIT_SIZE;
    return 1;
}

int DestroyStack(SqStack *S)
{
    free((*S).base);
    (*S).base=NULL;
    (*S).top=NULL;
    (*S).stacksize=0;
    return 1;

}

int ClearStack(SqStack *S)
{
    S->top=S->base;
    return 1;
}

int StackEmpty(SqStack *S)
{
    if((*S).top == (*S).base )
        return 1;
    else 
        return 0;

}

int StackLength(SqStack *S)
{
    return S->top - S->base;
}

int GetTop(SqStack *S,SElemType *e)
{
    if(S->top>S->base)
    {
        *e=*(S->top - 1);
        return 1;
    }else 
        return 0;
}

int Push(SqStack *S,SElemType e)
{
    if ( S->top - S->base >= S->stacksize )
    {
        S->base=(SElemType *) realloc (S->base,(S->stacksize + STACKINCREMENT) * sizeof(SElemType));
        if(!S->base)
            exit(3);
        S->top = S->base + S->stacksize;
        S->stacksize += STACKINCREMENT;
    }
    *(S->top)++=e;
    return 1;
}

int Pop(SqStack *S)
{
    if(S->top == S->base)
        return 0;
     *--(S->top);
    return 1;
}

int StackTraverse(SqStack *S,int (*visit)(SElemType))
{
    while(S->top > S->base){
        visit(*(S->base)++);
    }    
    printf("\n");    
    return 1;
}


int copy(int c)
{
    fputc(c,stdout);
    return 1;
}

void LineEdit()
{
    SqStack s;
    char ch,*c;
    InitStack(&s);
    printf("please input streams,ctrl+z to quit:\n");
    ch=getchar();
    while( ch != EOF )
    {
        while( ch != EOF && ch != '\n')
        {
            switch(ch)
            {
                case '#':Pop(&s);
                         break;
                case '@':ClearStack(&s);
                         break;
                default:Push(&s,ch);


            }
            ch=getchar();
        }
        StackTraverse(&s,copy);
        ClearStack(&s);
        if( ch != EOF)
            ch = getchar();
    }
    DestroyStack(&s);
}

int main(){
        LineEdit();
}