c - 按名称对队列进行排序不起作用

Question

我应该编辑程序，以便它按某种顺序对队列进行排序。我已经弄清楚如何对评级(数字)进行升序和降序排列，但我无法按艺术家(名称)进行排序。不知怎的，它就是没有像我想要的那样工作。 “le_item_artist”应该使输入的名称按应有的方式从 a 到 z 排序，但事实并非如此。你能告诉我出了什么问题吗？代码如下:

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

struct track
{
    char artist[20];
    char title[20];
    int rating; 
};

void print_item(any i)
{
    printf("(%i,'%s','%s')",
        ((struct track*)i)->rating,
        ((struct track*)i)->artist,
        ((struct track*)i)->title);
}

int le_item_desc(any i, any j)
{
    return ((struct track*)i)->rating <= ((struct track*)j)->rating;
}

int le_item_asc(any i, any j)
{
    return ((struct track*)i)->rating >= ((struct track*)j)->rating;
}

int le_item_artist(any i, any j)
{
    return ((struct track*)i)->artist >= ((struct track*)j)->artist;
}


int main(int argc, char **argv)
{
    char order;

    //Select sorting menu
    printf("Please select one of the following\n");
    printf("(a)scanding\n");
    printf("(d)escending\n");
    printf("Your option: ");

    scanf("%c", &order);

    pqueue *pq = new_bounded_pqueue(5,le_item_desc);
    pqueue *pq2 = new_bounded_pqueue(5,le_item_asc);
    pqueue *pq3 = new_bounded_pqueue(5,le_item_artist);

    struct track *it;
    int i;

    switch(order){
    case 'D':
    case 'd': for(i=0; i<3; i++) {
            it = (struct track*)malloc(sizeof(struct track));
            printf("rating artist title? ");scanf(" %i %s %s", &(it->rating), it->artist, it->title);
            pqueue_insert(pq,it);
            pqueue_print(pq,print_item);
            printf("\n\n");
    }
    for(i=0; i<3; i++) {
        pqueue_dequeue(pq);
        pqueue_print(pq,print_item);
        printf("\n\n");
    }
    break;
    case 'A':
    case 'a': for(i=0; i<3; i++) {
            it = (struct track*)malloc(sizeof(struct track));
            printf("rating artist title? ");scanf(" %i %s %s", &(it->rating), it->artist, it->title);
            pqueue_insert(pq2,it);
            pqueue_print(pq2,print_item);
            printf("\n\n");
    }
    for(i=0; i<3; i++) {
        pqueue_dequeue(pq2);
        pqueue_print(pq2,print_item);
        printf("\n\n");
    }
    break;
    case 'N':
    case 'n': for(i=0; i<3; i++) {
            it = (struct track*)malloc(sizeof(struct track));
            printf("rating artist title? ");scanf(" %i %s %s", &(it->rating), it->artist, it->title);
            pqueue_insert(pq3,it);
            pqueue_print(pq3,print_item);
            printf("\n\n");
    }
    for(i=0; i<3; i++) {
        pqueue_dequeue(pq3);
        pqueue_print(pq3,print_item);
        printf("\n\n");
    }
    break;
    default: printf("Error, wrong character!\n");
    }   

}

Answer 1

le_item_artist需要使用strcmp来比较两个字符串。当前的代码只是比较两个指针值，这不会执行您想要的操作。 – user3386109