Learn C, C++ Programming

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           Nested structure in C is nothing but structure within structure. One structure can be declared inside other structure as we declare structure members inside a structure. The structure variables can be a normal structure variable or a pointer variable to access the data. You can learn below concepts in this section.

1. Structure within structure in C using normal variable
2. Structure within structure in C using pointer variable

1. Structure within structure in C using normal variable:

           This program explains how to use structure within structure in C using normal variable. “student_college_detail’ structure is declared inside “student_detail” structure in this program. Both structure variables are normal structure variables.

Please note that members of “student_college_detail” structure are accessed by 2 dot(.) operator and members of “student_detail” structure are accessed by single dot(.) operator.

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

struct student_college_detail
{
    int college_id;
    char college_name[50];
};

struct student_detail 
{
    int id;
    char name[20];
    float percentage;
    // structure within structure
    struct student_college_detail clg_data;
}stu_data;

int main() 
{
    struct student_detail stu_data = {1, "Raju", 90.5, 71145,
                                       "Anna University"};
    printf(" Id is: %d n", stu_data.id);
    printf(" Name is: %s n", stu_data.name);
    printf(" Percentage is: %f nn", stu_data.percentage);

    printf(" College Id is: %d n", 
                    stu_data.clg_data.college_id);
    printf(" College Name is: %s n", 
                    stu_data.clg_data.college_name);
    return 0;
}

Output:

Structure within structure in C using pointer variable:

           This program explains how to use structure within structure in C using pointer variable. “student_college_detail’ structure is declared inside “student_detail” structure in this program. one normal structure variable and one pointer structure variable is used in this program.

Please note that combination of .(dot) and ->(arrow) operators are used to access the structure member which is declared inside the structure.

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

struct student_college_detail
{
    int college_id;
    char college_name[50];
};

struct student_detail 
{
    int id;
    char name[20];
    float percentage;
    // structure within structure
    struct student_college_detail clg_data; 
}stu_data, *stu_data_ptr;

int main() 
{
  struct student_detail stu_data = {1, "Raju", 90.5, 71145, 
                                    "Anna University"};
    stu_data_ptr = &stu_data;

    printf(" Id is: %d n", stu_data_ptr->id);
    printf(" Name is: %s n", stu_data_ptr->name);
    printf(" Percentage is: %f nn", 
                         stu_data_ptr->percentage);

    printf(" College Id is: %d n", 
                         stu_data_ptr->clg_data.college_id);
    printf(" College Name is: %s n", 
                      stu_data_ptr->clg_data.college_name);

    return 0;
}

Output:

……

Continue on C – Structure Memory Allocation….

Continue on C – Structure Padding….

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