Question

我正在尝试创建一个指向另一个结构数组的指针数组。但是，我很困惑我是否应该将新数组声明为int或与第一个数组相同的类型，因为它将保留指针。这就是我到目前为止所做的：

struct inventoryItem
{
    int itemNumber;
    int itemsInStock;
    float cost;
    float retailPrice;

};


int main()
{
    printf("Enter the number of slots needed in the array: ");
    int size;
    scanf("%d", &size);

    //array of items
    struct inventoryItem *inventory; //use pointer to item 
    inventory =(struct inventoryItem *) malloc(sizeof(struct inventoryItem)*size); //create array to store inventoryItem with size 'size'

    //array of index
    //int *indexArray = (int*) malloc(sizeof(int)*size); 
    struct inventoryItem *indexArray; //use pointer to item 
    indexArray =(struct inventoryItem *) malloc(sizeof(struct inventoryItem)*size); //create array to store inventoryItem with size 'size'

    //fill array contents
    for(int i = 0; i < size; i++)
    {
        printf("Enter item %d number: ", i);
        scanf("%d", &inventory[i].itemNumber);

        printf("Enter item %d stock: ", i);
        scanf("%d", &inventory[i].itemsInStock);

        printf("Enter item %d cost: ", i);
        scanf("%f", &inventory[i].cost);

        printf("Enter item %d price: ", i);
        scanf("%f", &inventory[i].retailPrice);
    }

    for(int i = 0; i < size; i++)
    {
        printf("Item %d number: %d\n", i, inventory[i].itemNumber);
        printf("Item %d stock: %d\n", i, inventory[i].itemsInStock);
        printf("Item %d cost: %f\n", i, inventory[i].cost);
        printf("Item %d retail price: %f\n", i, inventory[i].retailPrice);
    }


    //struct inventoryItem *header = inventory;
    //struct inventoryItem *ptr = inventory;
    for(int i = 0; i < size; i++)
    {
        indexArray[i] = &inventory[i]; 
            //problem here, it says "no operator '=' matches these operands"

    }
}

编辑：现在我创建了数组，如何使用indexArray打印库存内容？

Answer 1

你应该分配指针数组：

struct inventoryItem **indexArray;
indexArray = (struct inventoryItem **)malloc(sizeof(struct inventoryItem*)*size);

Answer 2

将`indexArray'声明为

struct inventoryItem **indexArray;

使用

创建它

indexArray =(struct inventoryItem **) malloc(sizeof(struct inventoryItem *)*size);

并填写

indexArray[i] = &inventory[i];

或

indexArray[i] = inventory + i;

Answer 3

为了便于阅读，最好先做一个typedef：

typedef struct inventoryItem Inv;

如果要创建指向struct数组的指针数组，而不是

Inv* indexArray = malloc(sizeof(Inv)*size);

写

Inv** indexArray = malloc(sizeof(Inv*)*size);

Answer 4

struct inventoryItem **inventory; //use pointer to item 
inventory =(struct inventoryItem **) malloc(sizeof(struct inventoryItem*) * size);

Answer 5

到目前为止，您有两个指针，每个指针指向一个结构数组的第一项。

如果你想要一个T数组，那么你使用T[]表示法，指针与其他类型没有区别。所以

struct inventoryItem *foo[10];
foo[0] = malloc( size * sizeof *foo[0] );

等。在此示例中，inventory替换为foo[0]。你当然可以写struct inventoryItem *inventory = foo[0];

当然，如果在编译时不知道您需要的数组数量，也可以动态分配foo：

struct inventoryItem **foo = malloc( 10 * sizeof *foo );

指向另一个数组的指针数组

5 个答案: