使用合并排序对结构数组进行排序

Question

因此，我有一个名为product的结构，并且有一系列产品。

我正在尝试使用合并排序按产品价格对数组进行排序，问题是我的代码没有交换任何内容，我也不明白为什么。如果有人可以帮助我，我将不胜感激。

结构：

typedef struct product {
    int ident;      /* idp of a product */
    char desc[64];  /* string that describes a product eg. "bread" */
    int price;      /* price of the product */
    int weight;     /* weight of the product eg. 2kg */
    int quant;      /* quantity of the product in stock */
    int state_prod; /* state of a product, if 1 it is in the system else is 0 and is not in the sistem */
} product;

合并排序算法

void mergesort_price(product a[], int left, int right) {
    int m = (right + left) / 2;
    if (right <= left)
      return;
    mergesort_price(a, left, m);
    mergesort_price(a, m + 1, right);
    merge_price(a, left, m, right);
}

void merge_price(product a[], int left, int m, int right) { 
    int i, j, k;
    for (i = m + 1; i > left; i--) 
        aux[i - 1] = a[i - 1];
    for (j = m; j < right; j++)
        aux[right + m - j] = a[j + 1];
    for (k = left; k <= right; k++)
        if (aux[j].price < aux[i].price || i > m)
            a[k] = aux[j--];
        else
        if ((aux[j].price == aux[i].price) || i > m) {
            if ((aux[j].ident < aux[i].ident) || i > m) {
                a[k] = aux[j--];
            }
        } else
            a[k] = aux[i++];
}

示例：

我的输入：

desc: pao, price:2, weight: 2, quant:200
desc: ovos, price:1, weight: 1, quant:100
desc: iscas, price:3, weight: 3, quant:300
desc: fiambre, price:2, weight: 2, quant:200
desc: queijo, price:2, weight: 2, quant:200

正确的输出：

desc: ovos, price:1, weight: 1, quant:100
desc: pao, price:2, weight: 2, quant:200
desc: fiambre, price:2, weight: 2, quant:200
desc: queijo, price:2, weight: 2, quant:200
desc: iscas, price:3, weight: 3, quant:300

程序：

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

#define MAX_PROD 10000 /* max products in the system */

typedef struct product {
   int ident;      /* idp of a product */
   char desc[64];  /* string that describes a product eg. "bread" */
   int price;      /* price of the product */
   int weight;     /* weight of the product eg. 2kg */
   int quant;      /* quantity of the product in stock */
   int state_prod; /* state of a product, if 1 it is in the system else is 0 and is not in the system */
} product;

product p1 = { 0, "pao", 2, 2, 200, 1 };
product p2 = { 1, "ovos", 1, 1, 100, 1 };
product p3 = { 2, "iscas", 3, 3, 300, 1 };
product p4 = { 3, "bacon", 2, 5, 400, 1 };
product p5 = { 4, "abacate", 2, 6, 500, 1 };

product sistem[5] = {};  /* array that contains the products */
product sistem2[5] = {}; /* Will be used has a copy of sistem */

sistem[5] = { p1, p2, p3, p4, p5}
product aux[5]; /* Auxliar array used in mergesort */

void mergesort_price(product a[], int left, int right) {
    int m = (right + left) / 2;
    if (right <= left)
        return;
    mergesort_price(a, left, m);
    mergesort_price(a, m + 1, right);
    merge_price(a, left, m, right);
}

void merge_price(product a[], int left, int m, int right) { 
    int i, j, k;
    for (i = m + 1; i > left; i--) 
        aux[i - 1] = a[i - 1];
    for (j = m; j < right; j++)
        aux[right + m - j] = a[j + 1];
    for (k = left; k <= right; k++)
        if (aux[j].price < aux[i].price || i > m)
            a[k] = aux[j--];
        else if ((aux[j].price == aux[i].price) || i > m) {
            if ((aux[j].ident < aux[i].ident) || i > m) {
                a[k] = aux[j--];
            }
        } else
            a[k] = aux[i++];
}

void print_array(product arr[]) {
    int i;
    for (i = 0; i < 5; i++) {
         printf("* %s %d %d %d\n", arr[i].desc, arr[i].price, arr[i].quant, arr[i].ident);
    }
}

void copy_el(product source[], product dest[], int size) {
    int i;
    for (i = 0; i < size; i++) {
        dest[i] = source[i];
    }
}

int main() {   
    copy_el(sistem, sistem2, 5);
    printf("The products in the system are:\n");
    print_array(sistem);

    printf("\nSorted products by price in the system:\n");
    mergesort_price(sistem2, 5, 0);
    print_array(sistem2);

    return 0;
}

[我知道我键入的输入未在程序中进行编码，我只是以这种方式给出的输入作为示例，以使其更易于理解。

Answer 1

记住我在最前面的评论中提到的，您的for循环是not