重置结构数组指针

Question

我想处理txt文件中给出的数据。它有几行和两列。对于我的算法，我必须使用结构数组，以便每个数组项对应于txt文件中的一行。在一行内，有一个字符串和一个数字。因此，我创建了两个结构成员。我一行一行地填写结构。但是，不知何故，我必须将结构数组指针重置为第一个元素，这是我无法实现的。

#include <stdio.h>

void loadData(struct item *inputItems, FILE *inputStream);
void printItemStructure(struct item *itemArray, int nItems);

struct item{
    char *tag;
    double itemSize;
};


int main()
{
    /* Handle the input file */
    char *inputFileName = "d:\\Users\\User\\Downloads\\input.txt";
    FILE *input;
    input = fopen(inputFileName, "r");
    if (input == NULL){
        printf("Could not open the file for reading.");
        return -1;
    }
/* ========== Read the file content to the input structure ========== */

    /*Determine the number of items by counting the rows of the input file */
    int N = 0; /* number of items */
    int nChars = -1; /* number of characters (exclude EOF character) */
    char penChar; /* penultimate character */
    char currentChar = ' '; /* last character read from the file stream */
    char lastChar; /* number of characters */
    while (!feof(input)){
        lastChar = currentChar;
        currentChar = fgetc(input);
        nChars++;
        if (currentChar == '\n')
            N++;
    }
    if (lastChar != '\n' /* the file does not end with '\n' ... */
        && nChars != 0)  /* ... and is not empty */
        N++;

    /* Process data row-by-row */
    struct item *inputItems = calloc(N, sizeof(struct item));
    struct item *origItems = inputItems; /* this will be reseted */
    loadData(inputItems, input);

    inputItems = origItems;
    printItemStructure(inputItems, N);

    /* Close the file */
    fclose(input);

    return 0;
}

void loadData(struct item *inputItems, FILE *inputStream){
    rewind(inputStream);
    char *start = inputItems[0].tag;
    char row[200];
    int rowSize = 200;
    int i = 0;
    char title[200];
    double size;
    while (fgets(row, rowSize, inputStream)){
        sscanf(row, "%s %lf", title, &size); // why doesn't it work directly?
        inputItems[i].tag = title;
        inputItems[i].itemSize = size;
        printf("%s\n", row);
        i++;
    }
}

void printItemStructure(struct item *itemArray, int nItems){
    /* Print the members of the item structure array for debugging purposes */
    for (int j = 0; j<nItems; j++)
    {
        printf("\nitemArray[%d]\n   Tag: %s,   Size: %lf\n",
            j, itemArray[j].tag, itemArray[j].itemSize);
    }
}

为什么我无法重置*tag结构数组的inputItems字段？ input.txt文件包含：

Film1 1.8
Film2   4.25