C Structure

* A structure is a user-defined compound data type which consists of data members related to a person or an item. It is referred to record in other programming languages.

Structure Declaration

In C, you can declare a structure using the 'struct' keyword. A structure is a user-defined data type that allows you to group together variables of different data types under a single name. Here's the basic syntax for declaring a structure:

struct structure_name {
    data_type member1;
    data_type member2;
    // More members...
};

Here's a breakdown of the elements in a structure declaration:

⤑ 'struct': This keyword is used to define a structure in C.

⤑ 'structure_name': Replace this with the desired name for your structure. This is the name you'll use to create variables of this structure type.

⤑ 'data_type member1;', 'data_type member2;': These are the members (fields) of the structure. Each member has a data type (e.g., 'int', 'char', 'float', or another custom structure) and a name (e.g., 'member1', 'member2'). You can declare as many members as you need within the structure.

Here's an example of declaring a simple structure in C:

#include ＜stdio.h>

struct student {
    int roll;
    char name[50];
    float percentage;
};

int main() {
    int n;
    printf("How many students' data do you want to store? (max. 9): ");
    scanf("%d", &n);

    if (n > 9 || n < 1) {
        printf("Please enter a number between 1 and 9.\n");
        return 1;  // Exit with an error code
    }

    struct student std[9]; // Use an array of size 9, as the maximum is 9.

    for (int i = 0; i < n; i++) {
        printf("\nEnter %d no. student roll: ", i + 1);
        scanf("%d", &std[i].roll);

        printf("Enter %d no. student name: ", i + 1);
        scanf("%49s", std[i].name);

        printf("Enter %d no. student percentage: ", i + 1);
        scanf("%f", &std[i].percentage);
    }

    printf("<---Data Store Completed--->\n");

    for (int i = 0; i < n; i++) {
        printf("\n%d no. student roll number: %d\n", i + 1, std[i].roll);
        printf("%d no. student name: %s\n", i + 1, std[i].name);
        printf("%d no. student percentage: %.2f\n", i + 1, std[i].percentage);
    }

    return 0;  // Exit with a success code
}

How many students' data do you want to store? (max. 9): 3

Enter 1 no. student roll: 21
Enter 1 no. student name: Ayan
Enter 1 no. student percentage: 64.78

Enter 2 no. student roll: 22
Enter 2 no. student name: Sanvi
Enter 2 no. student percentage: 84.45

Enter 3 no. student roll: 23
Enter 3 no. student name: Alan
Enter 3 no. student percentage: 78.89
<---Data Store Completed--->   

1 no. student roll number: 21  
1 no. student name: Ayan       
1 no. student percentage: 64.78

2 no. student roll number: 22  
2 no. student name: Sanvi      
2 no. student percentage: 84.45

3 no. student roll number: 23  
3 no. student name: Alan
3 no. student percentage: 78.89

This code is a basic example of how to use structures to store and manage data for multiple students. It includes error handling to ensure that the user enters a valid number of students. The program then collects and displays the student data accordingly.