c - 我的动态数组有问题

Question

当添加超过13个元素时，结果似乎不正确!我的代码如下!当添加 12 个元素时，结果为

the NO.0 is 0
the NO.1 is 1
the NO.2 is 2
the NO.3 is 3
the NO.4 is 4
the NO.5 is 5
the NO.6 is 6
the NO.7 is 7
the NO.8 is 8
the NO.9 is 9
the NO.10 is 10
the NO.11 is 11

当再添加一个时，结果改变了很多，我不知道这里发生了什么:

the NO.0 is 0
the NO.1 is 1
the NO.2 is 2
the NO.3 is 3
the NO.4 is 4
the NO.5 is 5
the NO.6 is 6
the NO.7 is 7
the NO.8 is 0
the NO.9 is 1
the NO.10 is 2
the NO.11 is 3
the NO.12 is 12

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

typedef struct dynarray myarray;
struct dynarray {
    int size;
    int length;
    int *array;
};

myarray *create(void) {
    /* TODO: define for arrays */
    myarray *da;
    da = malloc(sizeof(myarray));
    da->size = 0;
    da->length = 3;
    da->array = (int *)malloc(da->length * sizeof(int));
    return da;
}


void add(myarray *array, int val) {
    int i;
    int length = array->length;
    int size = array->size;
    int *temp;
    //printf("da->size1 = %d\nda->length1 = %d\n",array->size,array->length);

    if (size == length) {
        temp = (int *)malloc(length * sizeof(int));
        for (i = 0; i<size; i++) {
            temp[i] = array->array[i];
            printf("%d,", array->array[i]);
        }


        //printf("!@#$@#$=%d\n",array->length);

        array->array = (int*)realloc(array->array, sizeof(int)*length);
        for (i = 0; i<size; i++)
            array->array[i] = temp[i];
        array->length *= 2;
        length *= 2;
    }
    if (size <length) {
        array->array[size] = val;
        printf("array[%d]====%d\n", size, array->array[size - 1]);
        array->size++;
    }
}


int main() {
    int i;
    myarray *da = create();
    //printf("da->size = %d\nda->length = %d\n",da->size,da->length);

    for (i = 0; i<12; i++)
        add(da, i);
    // printf("a->size = %d\nda->length = %d\n",da->size,da->length);
    for (i = 0; i<12; i++)
        printf("the NO.%i is %d\n", i, da->array[i]);
}

Answer 1

正如评论中所说，您滥用了 realloc 并且没有正确编辑长度。添加内容如下:

void add(myarray *array, int val){
    int length = array->length;
    int size = array->size;

    if(size == length){
        array->length *= 2;
        array->array=(int*)realloc(array->array,sizeof(int)*length);
    }
    array->array[size] = val;
    array->size++;
}