从C中的typedef结构排序数组

Question

问题:尝试对来自我创建的typedef结构(电话簿)的数组进行排序.

目标:尝试构建一个允许用户添加,删除,排序和打印电话簿的电话簿.

我在哪里:除了排序外,我的一切都在运作.我通过阅读各种网络论坛/示例拼凑了一个排序函数,但无法让它工作.

我遇到的问题:添加条目(工作正常)后,如果您尝试对条目进行排序,该函数会将这些条目的值清零,当您打印电话簿时,它会将所有条目显示为空白.它应按姓氏的字母顺序排序.

这是我的排序算法:

void Sort (phone phonebook[])
{
    phone temp;
    int i;  int j;

    for (i=0; i<19; i++)
    {
        for (j=i+1; j<19; j++)
        {
            if (strcmp(phonebook[i].Surname, phonebook[j].Surname) > 0)
            {
                temp=phonebook[i];
                phonebook[i]=phonebook[j];
                phonebook[j]=temp;

            }
        }
    }
}

有任何想法吗？

---

完整代码:

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

//typedef struct to define what's in the phonebook
typedef struct PhoneBookContacts
{
    char Name[20];
    char Surname[20];
    char PhoneNumber[20];
} phone;

//Function prototypes
void AddEntry (phone[]);
void DeleteEntry (phone[]);
void PrintEntry (phone[]);
void Sort (phone[]);
int counter = 0; //Global counter variable used to keep track of number of contacts

//Begin main function
int main (void)
{
    phone phonebook[20]; //Phonebook instance
    char userChoice; //Variable to use to select menu choice

    while (userChoice != 'Q') {
        printf ("***************\n");
        printf ("Please enter a command:\n");
        printf("'A': Add an entry\n");
        printf("'D': Delete an entry\n");
        printf("'S': Sort entries\n");
        printf("'P': Print the phonebook\n");
        printf("'Q': Quit\n");
        printf ("***************\n");

        scanf("%s", &userChoice);  //Stores menu choice into variable userChoice

        // Add Contact
        if (userChoice == 'A')
            AddEntry(phonebook);

        //Remove Contact
        if (userChoice == 'D')
            DeleteEntry (phonebook);

        //Print Contacts
        if (userChoice == 'P')
            PrintEntry(phonebook);

        //Sort Contacts
        if (userChoice == 'S')
            Sort(phonebook);

        //Quit
        if (userChoice == 'Q') {
            printf("Phonebook will now quit.");
            return 0;
        }
    }
}

//Function Definition to Add Contacts to the Phonebook
void AddEntry (phone phonebook[]) {
    counter++; //global counter increase

    printf("\nFirst Name: ");
    scanf("%s", phonebook[counter-1].Name); //counter-1 b/c arrays start at 0

    printf("Last Name: ");
    scanf("%s", phonebook[counter-1].Surname);

    printf("Phone Number (XXX-XXX-XXXX): ");
    scanf("%s", phonebook[counter-1].PhoneNumber);

    printf("\n%s added to phonebook\n", phonebook[counter-1].Name); //tell user friend added
}

void DeleteEntry (phone phonebook[])
{
    int x = 0;
    char deleteName[20];  // Temp string to compare to existing phonebook
    char deleteSurname[20];  //temp string
    char nullStr[20] = {"\0"};  // empty string to remove phonenumber

    printf("\nEnter name: ");
    scanf("%s", deleteName); //place into temp string
    printf("Enter Surname: ");
    scanf("%s", deleteSurname); //place into temp string

    for (x = 0; x < counter; x++)
    {
        if (strcmp(deleteName, phonebook[x].Name) == 0) //compare deleteName to phonebook.Name
        {
            for (x = 0; x < counter; x++)
            {
                if (strcmp(deleteSurname, phonebook[x].Surname) == 0) //If deleteSurname matches phonebook.Surname
                {
                    strcpy(phonebook[x].Name, nullStr); //Put null into Name
                    strcpy(phonebook[x].Surname, nullStr); //Null into Surname
                    strcpy(phonebook[x].PhoneNumber, nullStr); //Null into PhoneNumber
                    printf("Contact removed from phonebook.\n");
                    counter--;
                    break;
                }
            }

        }
        else printf("Invalid entry--try again.\n");
    }
}

// Function def to print contacts
void PrintEntry (phone phonebook[]) {
    int x = 0;
    printf("\nPhonebook entries:\n");

    for ( x = 0; x < counter; x++) {
        printf("\n(%d)\n", x+1); //Show contact number
        printf("Name: %s %s\n", phonebook[x].Name, phonebook[x].Surname); //Name
        printf("Number: %s\n", phonebook[x].PhoneNumber); //Number
    }
}

void Sort (phone phonebook[]) {
    phone temp;
    int i;  int j;

    for (i=0; i<19; i++) {
        for (j=i+1; j<19; j++) {
            if (strcmp(phonebook[i].Surname, phonebook[j].Surname) > 0) {
                temp=phonebook[i];
                phonebook[i]=phonebook[j];
                phonebook[j]=temp;
            }
        }
    }
}

Answer 1

您可以使用以下qsort可用的已实现的排序功能函数stdlib.h:

int SortFunc(void* a, void* b) {
    phone *p1 = (phone*)a;
    phone *p2 = (phone*)b;

    return strcmp(p1->Surname, p2->Surname);
}

void Sort (phone phonebook[]) {
    qsort(phonebook, counter, sizeof(phone), &SortFunc);
} 

该函数通常是Quicksort,但这取决于C库实现的决定.

更新:

空白列表是因为排序是相反的并且总是对电话簿的所有19个项目进行排序,将空白的项目与真实的项目进行比较.如果电话簿上的条目少于19个,则实际数据将出现在电话簿阵列的末尾.

您原来的排序功能总是工作几乎确定.只需更改两者的结束条件即可.

void Sort (phone phonebook[]) {
    phone temp;
    int i;  int j;

    for (i=0; i<counter; i++) {
        for (j=i+1; j<counter; j++) {
            if (strcmp(phonebook[i].Surname, phonebook[j].Surname) > 0) {
                temp=phonebook[i];
                phonebook[i]=phonebook[j];
                phonebook[j]=temp;
            }
        }
    }
}

我也更新了Sort上面的内容.