C用户输入数组的大小 [英] C User input size of Array

问题描述

我正在尝试编写一个程序，该程序可以根据用户输入创建具有大小的数组，然后将结构存储在其中. 该结构将包含两个int和两个float.

I am trying to write a program that can create an array with size based on the user input and then store structs inside. The struct will contain two ints and two floats.

我的主要问题是，如何根据用户输入创建具有大小的数组? 这是我到目前为止的内容:

My main problem is, how do I create an array with size based on the user input? This is what I have so far:

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


int main()
{
    printf("Enter the number of slots needed in the array: ");
    int size;
    scanf("%d", &size);
    struct inventoryItem inventory[size]; //problem here

}

对于使用C语言进行编程，我是一个新手，因此不需太复杂的解决方案.

I am fairly new to programming in C so a solution that is not too complex would be appreciated.

因此，既然我已经解决了第一部分的问题，我现在正尝试创建第二个数组，该数组包含指向第一个数组的数据(索引)的指针. 现在的问题是我不知道如何创建一个for循环，该循环可以将指针指向第一个数组并将其存储到第二个数组中. 我将indexArray声明为"int"类型，不确定是否正确.

So now that I have the first part solved, I am now trying to create a second array that holds pointers to the first array's data (an index). Now the problem is I do not know how to create a for loop that can take the pointers to the first array and store them into the second. I declared the indexArray as type 'int' and am not sure if that is right.

这是我到目前为止所拥有的:

This is what I have so far:

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); //not sure if this is right

    //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);
    }

    //stuck here

    //struct inventoryItem *header = inventory; //error here
    for(int i = 0; i < size; i++)
    {
        //indexArray[i] = inventory[i];
    }

}

推荐答案

您应该使用malloc动态分配数组的大小

You should use malloc to dynamically allocate the size of array

#include <stdlib.h>

int main()
{
    struct inventoryItem *inventory; //use pointer to item 
    printf("Enter the number of slots needed in the array: ");
    int size;
    scanf("%d", &size);

    //after you get the size input 
    inventory = malloc(sizeof(struct inventoryItem)*size);
}

最后，您应该使用free释放内存

In the end you should use the free to free the memory

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