编程范式 episode 6 实现stack 栈功能

//既然在这里开始，那就在这里结束。

实现stack 功能

____coding

_using subfunction to focus on the main aim of current function

_void* is not allowed to do arithmetic operation

_makde sure parameters are valid before using them,especially related to pointer.

_____assert测试

assert带有一个断言作为int 类型参数，断言是指正常情况下为真的表达式。assert是一个宏，但是用函数实现的。

当参数为0，编译停止，提供参数信息输出显示。调试结束后，取消assert测试，只需加上一句

#define NDEBUG 在#include "assert.h"之前。

____void * realloc(void * p, int size);

return the same pointer in the parameter.

if current space is not enough, than go to a new place ,a pointer will be returned correspondly. The orighinal dates will be coped into the new space,2 cases: 1,integars will be copied directly. 2,if char,will consider the dates as address pointing at the char,so in the new space ,also address is copied and stored....

____when dealing with pointers, make sure the pointer is valid one.use assert to perform the check.

____stark 的char 型实现。

typedef struct {

    uchar length;

    uchar allocSize;

    uchar* elem;

}stack;

void stackNew(stack *s);

void stackDispose(stack *s);

void stackPush(stack *s, uchar* date);

void stackPop(stack *s, uchar* date);

void stackNew(stack *s)

{

    assert(s!=NULL);

    s->length = ;

    s->allocSize = ;

    s->elem = malloc(*sizeof(uchar));

    assert(s->elem != NULL);

}

void stackDispose(stack *s)

{

    assert(s != NULL && s->elem != NULL);

    free(s->elem);

}

void stackPush(stack *s, uchar* date)

{

    assert(s!=NULL && date != NULL);

    if(s->length == s->allocSize)

    {

        s->allocSize *= ;

        s->elem = realloc(s->elem,s->allocSize);  //reallocate designate size

        assert(s->elem != NULL);

    }

    *(s->elem+s->length) = *date;    //s->elem[s->length-1] = *date;

    s->length += ;

}

void stackPop(stack *s, uchar* date)

{

    assert(s!=NULL && date!=NULL);

    assert(s->length >= );

    --s->length;

    *date = s->elem[s->length];

}

stack generic function

typedef struct {

    void* elem;

    uchar elemSize;

    uchar logicalLen;

    uchar allocSize;

}stack;

void stackNew(stack *s,uchar elemSize);

void stackDispose(stack *s);

void stackPush(stack *s,void* elemAdder);

void stackPop(stack *s,void* elemAdder);

void stackNew(stack *s,uchar elemSize)

{

    assert(s!=NULL);

    assert(elemSize >= );        //parameter check

    s->elemSize = elemSize;

    s->logicalLen = ;

    s->allocSize = ;

    s->elem = malloc(*elemSize);

    assert(s->elem != NULL);

}

void stackDispose(stack *s)

{

    assert(s != NULL && s->elem != NULL);

    free(s->elem);

}

static void stackGrow(stack*s)  // use static to prenvent the calling from other files.

{

    s->allocSize *= ;

    s->elem = realloc(s->elem,s->allocSize);  //reallocate designate size

    assert(s->elem != NULL);

}

void stackPush(stack *s,void* elemAdder)

{

//    assert(s!=NULL && elemAdder != NULL);

    if(s->logicalLen == s->allocSize)

    {

        ////Using subfunction to focuse one the key point.

        stackGrow(s);

    }

    ////   void* is not allowed to perform arithmetic operation

    void* target = (uchar*)s->elem + s->logicalLen * s->elemSize;

    memcpy(target,elemAdder,s->elemSize);

    s->logicalLen += ;

}

void stackPop(stack *s, void* elemAddre)

{

    //    assert(s!=NULL && elemAdder != NULL);

    assert(s->logicalLen >= );

    s->logicalLen -= ;;

    void* position = (uchar*)s->elem + s->logicalLen * s->elemSize;

    memcpy(elemAddre,position,s->elemSize);

}

int main()

{

    const char* friends[3] = {"a1","b2","c3"};

    stack stringStack;

    uchar i;

    uchar* copy;

    stackNew(&stringStack,sizeof(uchar**));

    for(i = ;i < ;i++)

    {

        copy =strdup(friends[i]);

        stackPush(&stringStack,&copy);

    }

    char *name;

    for(i = ; i < ; i++)

    {

        stackPop(&stringStack,&name);

        printf("%s\n",name);

        free(name);

    }

    stackDispose(&stringStack);

    return ;

}

//在之前的程序上修改新的功能时，多了出现bug的机会

一行一行检查，避免疏忽造成的错误

就算出错了也不要紧，一行一行找，总是可以找到问题。

这世界上再也没有比程序的运行更确定的事情，这也是我喜欢这一行的原因

巴特西

编程范式 episode 6 实现stack 栈功能_ to do

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