结构数组排序成员 [英] sorting members of structure array

问题描述

给定一个结构数组（C语言），我试图用数字顺序打印出性别组的结果，并在亚秩序。例如：

 结构员工{
焦炭性别[13]
焦炭名[13];
INT ID;
};
 

说我定义结构阵列像这样：

 结构员工信息[2] = {{男性，马特，1234}，{女性，杰西卡，2345}，{男性，乔希，1235}};
 

我怎么能去打印结果像

  1234马特
1235乔希
2345杰西卡
 

解决方案

您需要实现一个排序功能的结构，你需要比较

  INT比较（常量无效* S1，常量无效* S2）
{
  员工结构* E1 =（结构*员工）S1;
  员工结构* E2 =（结构*员工）S2;
  INT gendercompare = STRCMP（E1-＆GT;性别，E2-＆GT;性别）;
  如果（gendercompare == 0）/ *同性别等等排序ID * /
    返回E1-＆GT; ID  -  E2-＆GT; ID;
  其他
    返回-gendercompare; / *负提出男性作为第一个问题中* /
}
 

和再使用的qsort标准库。

 的qsort（数据，计数的sizeof（结构员工），比较）;
 

里面的比较功能，你可能要检查的ID都是平等的，那么你就可以按名称排序（同样使用的strcmp（）），但是你喜欢。

肯

编辑：刚刚编译和固定这件事。这里有一个小测试程序

 的#include＆LT;＆stdio.h中GT;
    ＃包括LT＆;＆stdlib.h中GT;    员工结构{
      焦炭性别[13];
      焦炭名[13];
      INT ID;
    };    INT比较（常量无效* S1，常量无效* S2）
    {
      员工结构* E1 =（结构*员工）S1;
      员工结构* E2 =（结构*员工）S2;
      INT gendercompare = STRCMP（E1-＆GT;性别，E2-＆GT;性别）;
      如果（gendercompare == 0）/ *同性别等等排序ID * /
        返回E1-＆GT; ID  -  E2-＆GT; ID;
      其他
        返回-gendercompare;
    }    主要（）
    {
      INT I;
      结构员工信息[] = {{男性，马特，1234}，{女性，杰西卡，2345}，{男性，乔希，1235}};      对于（I = 0;我3; ++ⅰ）
        的printf（％d个\\ t％S \\ t％S \\ n，信息[I] .ID，资讯[I] .gender，资讯[我]。名称）;      的qsort（资讯，3，的sizeof（结构员工），比较）;      对于（I = 0;我3; ++ⅰ）
        的printf（％d个\\ t％S \\ t％S \\ n，信息[I] .ID，资讯[I] .gender，资讯[我]。名称）;
    }
 

通过输出：

  $ ./a.exe
1234男马特
2345女杰西卡
1235男性乔希
1234男马特
1235男性乔希
2345女杰西卡
 

Given a structure array (in C) I am attempting to print out the results in groups of gender and in sub order by numerical order. For example:

struct employee{
char gender[13]
char name[13];
int id;
};

Say I define the structure array like so:

struct employee info[2]={{"male","Matt",1234},{"female","Jessica",2345},{"male","Josh",1235}};

How could I go about printing the results like

1234 Matt
1235 Josh


2345 Jessica

解决方案

You'll need to implement a sorting function that compares the structs as you require

int compare(const void *s1, const void *s2)
{
  struct employee *e1 = (struct employee *)s1;
  struct employee *e2 = (struct employee *)s2;
  int gendercompare = strcmp(e1->gender, e2->gender);
  if (gendercompare == 0)  /* same gender so sort by id */
    return e1->id - e2->id;
  else
    return -gendercompare;  /* the minus puts "male" first as in the question */
}

And then use qsort from the standard library.

qsort(data, count, sizeof(struct employee), compare);

Inside the compare function you may want to check for id being equal, then you can sort by name (also using strcmp()) however you like.

Ken

Edit: Just compiled and fixed this up. Here's a little test program

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

    struct employee{
      char gender[13];
      char name[13];
      int id;
    };

    int compare(const void *s1, const void *s2)
    {
      struct employee *e1 = (struct employee *)s1;
      struct employee *e2 = (struct employee *)s2;
      int gendercompare = strcmp(e1->gender, e2->gender);
      if (gendercompare == 0)  /* same gender so sort by id */
        return e1->id - e2->id;
      else
        return -gendercompare;
    }

    main()
    {
      int i;
      struct employee info[]={{"male","Matt",1234},{"female","Jessica",2345},{"male","Josh",1235}};

      for (i = 0; i < 3; ++i)
        printf("%d\t%s\t%s\n", info[i].id, info[i].gender, info[i].name);

      qsort(info, 3, sizeof(struct employee), compare);

      for (i = 0; i < 3; ++i)
        printf("%d\t%s\t%s\n", info[i].id, info[i].gender, info[i].name);
    }

With output:

$ ./a.exe
1234    male    Matt
2345    female  Jessica
1235    male    Josh
1234    male    Matt
1235    male    Josh
2345    female  Jessica

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