Aprenda Struct with Arrays and Other Structs

In some structures, it becomes necessary to use an array of nested structures when one object contains multiple related sub-objects. For example, if a student can take several courses, it makes sense to represent the courses as an array of structures inside the Student structure.

Example syntax:

OuterStruct.NestedStruct[1].NestedField;

To access an element of the nested structure array, you first refer to the outer structure, then use an index to select the desired element of the array, and finally access a specific field of that element.

Practical Example

Imagine each student has a name, age, and a set of courses. Each course contains its title, instructor, and number of credits.

main.c


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

struct Course {
    char name[50];
    char instructor[50];
    int credits;
};

struct Student {
    char name[50];
    int age;
    struct Course courses[3]; // array of nested structures
};

int main() {
    struct Student student;

    // Initialize student
    strcpy(student.name, "Alice Johnson");
    student.age = 20;

    // Initialize courses
    strcpy(student.courses[0].name, "Mathematics");
    strcpy(student.courses[0].instructor, "Dr. Smith");
    student.courses[0].credits = 4;

    strcpy(student.courses[1].name, "Computer Science");
    strcpy(student.courses[1].instructor, "Prof. Brown");
    student.courses[1].credits = 3;

    strcpy(student.courses[2].name, "History");
    strcpy(student.courses[2].instructor, "Dr. Green");
    student.courses[2].credits = 2;

    // Display information
    printf("Student: %s\n", student.name);
    printf("Age: %d\n", student.age);
    printf("Courses:\n");
    for (int i = 0; i < 3; i++) {
        printf("  Course %d: %s, Instructor: %s, Credits: %d\n",
               i + 1,
               student.courses[i].name,
               student.courses[i].instructor,
               student.courses[i].credits);
    }

    // Example of accessing a specific nested field
    printf("\nInstructor of the second course: %s\n", student.courses[1].instructor);

    return 0;
}

In this example, the Student structure has a courses array with three elements of type Course. Each course has its own title, instructor, and number of credits. To access a specific course, use the array index and dot operator: student.courses[1].instructor.

Using arrays of nested structures is useful for representing objects with repeated sub-objects, such as students with courses, stores with products, or books with authors.

Tarefa

Swipe to start coding

The student is represented by a structure Student which contains a fixed-size array of nested structures Course. Each course has a name, instructor, and number of credits. The function should iterate through all courses and sum the credits.

Implement a function calculateTotalCredits with a return type of int.

Inside the function, create an int variable total initialized to 0.
Use a for loop to iterate from 0 to the number of courses (3).
For each course, access credits and add it to total.
Return the final value of total.

Solução

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Seção 4. Capítulo 2

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Can you show me a code example of how to define these nested structures?

How do I access or modify a specific course for a student?

What are some other real-world scenarios where nested structure arrays are useful?

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