我被指派用 ANSI C 编写通用堆栈。它适用于原始数据类型。到这里为止,还没有出现任何大问题。
之后,我被要求重新编程我的应用程序,以便即使是复杂的数据类型也可以在我的堆栈上使用。我上周进行了搜索和研究,但没有发现任何有帮助的内容。
#include <stdlib.h>
#include <stdio.h>
#include <assert.h>
#include <string.h>
#include <stddef.h>
#include "genstacklib.h"
void (*freefn) (void*);
/*
* ToDo
*/
void GenStackNew(genStack *s, int elemSize, void (*freefunk) (void*))
{
s->elems = malloc (elemSize * GenStackInitialAllocationSize);
freefn = freefunk;
assert (s->elems != NULL);
s->elemSize = elemSize;
s->logLength = 0;
s->allocLength = GenStackInitialAllocationSize;
}
/*
* ULStackPush adds an element to the stack and allocates new memory if
* needed. If there is not enough memory, ULStackPush does nothing.
*/
void GenStackPush (genStack *s, const void *elemAddr)
{
/*assert (sizeof(*elemAddr) == s->elemSize);*/
assert (s->elems != NULL);
if (s->logLength == s->allocLength)
{
void *temp = NULL;
temp = realloc (s->elems, 2 * s->allocLength * s->elemSize);
assert (temp != NULL);
s->allocLength = 2 * s->allocLength;
s->elems = temp;
}
memcpy(currentval(s), elemAddr, s->elemSize);
s->logLength = s->logLength + 1;
}
void GenStackPop (genStack *s, const void *elemAddr)
{
assert (s->elems != NULL);
assert (s->logLength != 0);
(s->logLength)--;
memcpy((void *)elemAddr, currentval(s), s->elemSize);
}
void *currentval(genStack *s)
{
assert (s->elems != NULL);
return ((size_t*)s->elems + s->logLength * s->elemSize);
}
bool GenStackEmpty (const genStack *s)
{
assert (s->elems != NULL);
return s->logLength == 0;
}
void GenStackDispose (genStack *s)
{
assert (s->elems != NULL);
s->logLength = 0;
free (s->elems);
freefn();
}
/*
* ToDO
*/
void *freefn (void *) {
free
我的标题数据是:
#ifndef GENSTACKLIB_H
#define GENSTACKLIB_H
#include <stdbool.h>
#define GenStackInitialAllocationSize 4
typedef struct
{
void *elems;
int elemSize;
int logLength;
int allocLength;
} genStack;
void GenStackNew (genStack * s, int elemSize);
bool GenStackEmpty (const genStack * s);
void GenStackPush (genStack * s, const void *elemAddr);
void GenStackPop (genStack * s, const void *elemAddr);
void GenStackDispose (genStack * s);
void *currentval(genStack *s);
#endif
在第一个代码块中,我相信必须做的事情是在 ToDo 标记中。 如何才能将我的堆栈用于复杂的数据类型?
提前致谢
最佳答案
我没有看到像字符串这样的“复杂”类型有任何问题...指向字符串的指针和指向 int 的指针之间没有真正的区别。因此,只需存储指针(或指向指针的指针)就可以了。
所以元素不是“int”..元素是指向指针的指针。
非常“伪”C 代码形式的基本思想
typedef struct Wrapper
{
void * primitiveData;
} Wrapper;
void PrimitivePush(void * data)
{
Wrapper * w = malloc();
w->primitiveData = malloc();
memcpy(w->primitiveData, data);
ClassicComplexTypePush(&w)
}
ClassicComplexTypePush(void ** data)
{
push data to stack
}
关于复杂的通用堆栈,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/23242049/