C 语言泛型编程--stack实现

#ifndef _STACK_H_
#define _STACK_H_

typedef struct{
    void * elemType;
    int elemSize;
    int size;
    int capacity;
    void(*pfree)(void *);
}stack, * pstack;

void stackNew(pstack s, int elemSize, void(*pfree)(void *));

void stackDispose(pstack s);

void stackPush(pstack s, void * valAddr);

void stackPop(pstack s, void * valAddr);

#endif

#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
#include <string.h>
#include "stack.h"

static void sizeGrow(pstack s);

void stackNew(pstack s, int elemSize, void(*pfree)(void *))
{
    s->capacity = 4;
    s->elemSize = elemSize;
    s->size = 0;
    s->pfree = pfree;
    s->elemType = malloc(s->capacity * elemSize);
    assert(s->elemType);
}

void stackDispose(pstack s)
{
    if (s->pfree == NULL || s->size == 0)
        printf("don't need be free
");
    else
    {
        printf("free lefted elements
");
        for (int i = 0; i < s->size; ++i)
        {
            char * del = (char*)s->elemType + i * s->elemSize;
            s->pfree(del);
        }
    }
    free(s->elemType);
}

void stackPush(pstack s, void * valAddr)
{
    if (s->size == s->capacity)
        sizeGrow(s);
    void * target = s->elemType + s->size * s->elemSize;
    memcpy(target, valAddr, s->elemSize);
    ++s->size;
}

static void sizeGrow(pstack s)
{
    s->capacity *= 2;
    s->elemType = realloc(s->elemType, s->capacity * s->elemSize);
    assert(s->elemType);
}

void stackPop(pstack s, void * valAddr)
{
    assert(s->size);
    --s->size;
    void * source = s->elemType + s->size * s->elemSize;
    memcpy(valAddr, source, s->elemSize);
}

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "stack.h"

void strfree(void * pstr);

typedef struct student{
    char name[10];
    int age;
}student;

int main()
{
    student stu[5] = { { "Jonh", 10 }, {"Jim",11}, {"Allen",12}, {"Ewa",13}, {"Walle",14} };
    stack s;
    stackNew(&s, sizeof(student *), strfree);
    for (int i = 0; i < 5; ++i){
        student * pstu = (student *)malloc(sizeof(student));
        memcpy(pstu, &stu[i], sizeof(student));
        stackPush(&s, &pstu);
    }
    for (int i = 0; i < 3; ++i)
    {
        student *ps;
        stackPop(&s, &ps);
        printf("pop student %s.
", ps->name);
        free(ps);
    }
    stackDispose(&s);
    return 0;
}

void strfree(void * pstr)
{
    char * del = *(char**)pstr;
    free(del);
}