给定学生的记录,每个记录包含学生的ID,姓名和年龄。编写一个C程序来读取这些记录,并按名称按顺序显示它们。
例子:
Input: Student Records= {
{Id = 1, Name = bd, Age = 12 },
{Id = 2, Name = ba, Age = 10 },
{Id = 3, Name = bc, Age = 8 },
{Id = 4, Name = aaz, Age = 9 },
{Id = 5, Name = az, Age = 10 } }
Output:
{{Id = 4, Name = aaz, Age = 9 },
{Id = 5, Name = az, Age = 10 },
{Id = 2, Name = ba, Age = 10 },
{Id = 3, Name = bc, Age = 8 },
{Id = 1, Name = bd, Age = 12 } }
方法:此问题可通过以下步骤解决:
- 创建具有ID,名称和年龄字段的结构。
- 阅读结构中的学生记录
- 通过设置比较规则来定义比较器。在这里,可以借助strcmp()方法对名称进行排序。
- 现在借助qsort()方法基于已定义的比较器对结构进行排序。
- 打印排序的学生记录。
程序:
// C program to read Student records
// like id, name and age,
// and display them in sorted order by Name
#include
#include
#include
// struct person with 3 fields
struct Student {
char* name;
int id;
char age;
};
// setting up rules for comparison
// to sort the students based on names
int comparator(const void* p, const void* q)
{
return strcmp(((struct Student*)p)->name,
((struct Student*)q)->name);
}
// Driver program
int main()
{
int i = 0, n = 5;
struct Student arr[n];
// Get the students data
arr[0].id = 1;
arr[0].name = "bd";
arr[0].age = 12;
arr[1].id = 2;
arr[1].name = "ba";
arr[1].age = 10;
arr[2].id = 3;
arr[2].name = "bc";
arr[2].age = 8;
arr[3].id = 4;
arr[3].name = "aaz";
arr[3].age = 9;
arr[4].id = 5;
arr[4].name = "az";
arr[4].age = 10;
// Print the Unsorted Structure
printf("Unsorted Student Records:\n");
for (i = 0; i < n; i++) {
printf("Id = %d, Name = %s, Age = %d \n",
arr[i].id, arr[i].name, arr[i].age);
}
// Sort the structure
// based on the specified comparator
qsort(arr, n, sizeof(struct Student), comparator);
// Print the Sorted Structure
printf("\n\nStudent Records sorted by Name:\n");
for (i = 0; i < n; i++) {
printf("Id = %d, Name = %s, Age = %d \n",
arr[i].id, arr[i].name, arr[i].age);
}
return 0;
}
输出:
Unsorted Student Records:
Id = 1, Name = bd, Age = 12
Id = 2, Name = ba, Age = 10
Id = 3, Name = bc, Age = 8
Id = 4, Name = aaz, Age = 9
Id = 5, Name = az, Age = 10
Student Records sorted by Name:
Id = 4, Name = aaz, Age = 9
Id = 5, Name = az, Age = 10
Id = 2, Name = ba, Age = 10
Id = 3, Name = bc, Age = 8
Id = 1, Name = bd, Age = 12
注意:可根据比较器函数定义的规则,根据任何字段对结构进行排序。要了解有关比较器函数的更多信息。在C中参考qsort()的比较器函数
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