网易云课堂_C语言程序设计进阶_第5周：链表

5.1可变数组

5.2链表

5.1可变数组

Resizable Array

Think about a set of functions that provide a mechanism of resizable array of int.

Growable

Get the current size

Access to the elements

The Interface

Array array_create(int init_size);

void array_free(Array *a);

int array_size(const Array *a);

int *array_at(Array *a, int index);

void array_inflate(Array *a, int more_size);

头文件array.h

#include <stdio.h>

#ifndef _ARRAY_H_
#define _ARRAY_H_

typedef struct
{
    int *array;
    int size;
}Array;

Array array_create(int init_size);//清空数组
void array_free(Array *a);//返回数组元素数量
int array_size(const Array *a);//返回数组某个下标的值
int *array_at(Array *a, int index);//返回数组某个下标的值
int array_get(const Array *a, int index);//返回数组某个下标的值
void array_set(Array *a, int index, int value);//修改数组某个下标的值
void array_inflate(Array *a, int more_size);//增大数组

#endif

源文件array.c

#include "array.h"

const BLOCK_SIZE = 20;

//typedef struct
//{
//    int *array;
//    int size;
//}Array;

Array array_create(int init_size)//创建数组
{
    Array a;
    a.size = init_size;
    a.array = (int *)malloc(sizeof(int)*a.size);
    return a;
}

void array_free(Array *a)//清空数组
{
    free(a->array);
    a->array = NULL;
    a->size = 0;
}

int array_size(const Array *a)//返回数组元素数量
{
    return a->size;
}

int *array_at(Array *a, int index)//返回数组某个下标的值
{
    if (index >= a->size)
    {
        array_inflate(a, (index / BLOCK_SIZE + 1)*BLOCK_SIZE - a->size);
    }
    return &(a->array[index]);
}

int array_get(const Array *a, int index)//返回数组某个下标的值
{
    return a->array[index];
}

void array_set(Array *a, int index, int value)//修改数组某个下标的值
{
    a->array[index] = value;
}

void array_inflate(Array *a, int more_size)//增大数组
{
    int *p = (int *)malloc(sizeof(int)*(a->size + more_size));
    int i;
    for (i = 0; i < a->size; i++)
    {
        p[i] = a->array[i];
    }
    free(a->array);
    a->size += more_size;
}

void main()
{
    Array a = array_create(100);
    printf("%d
", array_size(&a));
    *array_at(&a, 0) = 10;
    printf("%d
", *array_at(&a, 0));

    int number;
    int cnt = 0;
    while (1)
    {
        /*scanf("%d", &number);
        *array_at(&a, cnt++) = number;*/
        scanf("%d", array_at(&a, cnt++));
    }
    
    array_free(&a);

    system("pause");
}

5.2链表

issues

Allocate new memory each time it inflates is an easy and clean way. BUT

It takes time to copy, and

may fail in memory restricted situation

必须保证：->箭头左边的指针，不能为空

    for (q = 0, p = head; p; q = p, p = p->next)
    {
        if (p->value == 1)
        {
            q->next = p->next;
        }
    }

 

 

必须保证：->箭头左边的指针，不能为空