C program to store Student records as Structures and Sort them by Age or ID

Given student’s records with each record containing id, name and age of a student. Write a C program to read these records and display them in sorted order by age or id.

Sorting by Age

Examples:

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 = 3, Name = bc, Age = 8 },
{Id = 4, Name = aaz, Age = 9 },
{Id = 2, Name = ba, Age = 10 },
{Id = 5, Name = az, Age = 10 },
{Id = 1, Name = bd, Age = 12 } }

Approach: This problem is solved in the following steps:

  • Create a structure with fields id, name and age.
  • Read the students records in the structure
  • Define a comparator by setting up rules for comparison. Here age can be sorted with the help of difference of the age of 2 students. (Student1 -> age – Student2 -> age)
  • Now sort the structure based on the defined comparator with the help of qsort() method.
  • Print the sorted students’ records.

Program:

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// C program to read Student records
// like id, name and age,
// and display them in sorted order by Age
  
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
  
// struct person with 3 fields
struct Student {
    char* name;
    int id;
    char age;
};
  
// setting up rules for comparison
// to sort the students based on age
int comparator(const void* p, const void* q)
{
    return (((struct Student*)p)->age - ((struct Student*)q)->age);
}
  
// 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 Age:\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;
}

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Output:


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 Age:
Id = 3, Name = bc, Age = 8 
Id = 4, Name = aaz, Age = 9 
Id = 2, Name = ba, Age = 10 
Id = 5, Name = az, Age = 10 
Id = 1, Name = bd, Age = 12







Sorting by Id




Examples:


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 = 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 } }



Approach: This problem is solved in the following steps:


    

  • Create a structure with fields id, name and age.
    • 

  • Read the students records in the structure
    • 

  • Define a comparator by setting up rules for comparison. Here id can be sorted with the help of difference of the id of 2 students. (Student1 -> id – Student2 -> id)
    • 

  • Now sort the structure based on the defined comparator with the help of qsort() method.
    • 

  • Print the sorted students’ records.
    • 



Program:











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// C program to read Student records 


// like id, name and age, 


// and display them in sorted order by ID 


  


#include <stdio.h> 


#include <stdlib.h> 


#include <string.h> 


  


// struct person with 3 fields 


struct Student { 


    char* name; 


    int id; 


    char age; 


}; 


  


// setting up rules for comparison 


// to sort the students based on ID 


int comparator(const void* p, const void* q) 


{ 


    return (((struct Student*)p)->id - ((struct Student*)q)->id); 


} 


  


// 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 ID:\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; 


} 



















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Output:


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 ID:
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






          
          
          
          

            

    

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