如何快速排序用户输入

Question

问题很简单，但越查越糊涂。我应该从我编写的结构代码中快速排序一个变量。但是，我不明白我应该如何对 em.fName 这样的变量进行快速排序，如果它在循环的每次迭代中都发生了变化。我查找的每个示例似乎都对 int 变量或预定义的字符数组进行排序。有人能给我指明从哪里开始的正确方向 and/or 举一个 C 语言的例子吗？谢谢，非常感谢。我 posted the full code here 因为我不想弄乱 post。

    typedef struct EmployeeRecord
    {
    STR21 lName;
    STR11 fName;
    char fullName[33];
    float hrs;
    float pay;
    float dfr;
    float gross;
    float ft;
    float st;
    float ssit;
    float net;

    } EmployeeRecord;

int main(void)
{
    EmployeeRecord em;

    do
    {
        counter++;
        em.dfr = em.ft = em.st = em.ssit = em.gross = em.hrs = em.pay = em.net = ovrtHrs = 0; //initalized to 0 and then changed by function if greater than 0
        printf("Please enter your FIRST name: ");
        scanf("%s",fName);
        printf("Please enter your LAST name: ");
        scanf("%s",lName);
        printf("Enter your payrate: ");
        scanf("%f",&em.pay);
        printf("Please enter your total hours: ");
        scanf("%f",&em.hrs);
        printf("Please enter the amount of deferred earnings: ");
        scanf("%f",&em.dfr);

        strcpy(fullName,lName); // combine last + ", " + first into full
                strcat(fullName,", ");
                strcat(fullName,fName);

        payTotal = payTotal + em.pay;
        dfrTotal = dfrTotal + em.dfr;

        em.gross = grossModule(&em.hrs,em.pay,&ovrtHrs); // call 3.4
        CalculateTaxes(&em.gross,&em.dfr,&em.ft,&em.st,&em.ssit); // call 3.0
        em.net = netModule(&em.gross,&em.ft,&em.st,&em.ssit); // cal 3.5

        hoursTotal = hoursTotal + em.hrs;
        overtimeTotal = overtimeTotal + ovrtHrs; // TOTALS
        grossTotal = grossTotal + em.gross;
        stateTotal = stateTotal + em.st;
        ssiTotal = ssiTotal + em.ssit;
        netTotal = netTotal + em.net;
        fedTotal = fedTotal + em.ft;

        fprintf(myreport,REPORTCOLUMNFORMATS,em.fullName,em.pay,em.hrs,em.gross,em.ft,em.ssit,em.net);
        fprintf(myreport,REPORTCOLUMNFORMATS3,ovrtHrs,em.st,em.dfr);


        printf("Would you like to continue, y/n? \n");
        scanf("%s",&ask);

    }while(ask == 'y' || ask == 'Y');

Answer 1

这里有一些建议：

你只读了一个EmployeeRecord，然后它被覆盖了，如果你想对它们进行排序，你必须把它们全部保存下来。您可以使用 realloc 动态更改保留 space 的大小或保持简单：
```
EmployeeRecord employees[100]; // will fail if more than 100 employees are added
...
// after em is complete:
employees[counter++] = em; // remove the other counter++
```

排序取自 wikibooks.org 并用普通 int 替换指针，使用索引而不是指针数学（更容易理解）并添加您必须填写的比较函数：

void swap(int a, int b)
{
    EmployeeRecord tmp = employees[a];
    employees[a] = employees[b];
    employees[b] = tmp;
}

int compare(int a, int b)
{
    // return -1 if employees[a] comes before employees[b]
    // return  1 if employees[a] comes after employees[b]
    // return  0 "if they have the same order"
    //           (stable algorithms e.g. mergesort won't change the order of those)
}

void quicksort(int begin, int end)
{
    int ptr;
    int split;
    if (end - begin <= 1)
        return;
    ptr = begin;
    split = begin + 1;
    while (++ptr <= end) {
        if (compare(ptr, split) > 0) { // sorts ascending
            swap(ptr, split);
            ++split;
        }
    }
    swap(begin, split - 1);
    quicksort(begin, split - 1);
    quicksort(split, end);
}

在用户决定不再继续后排序并创建报告。

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