In C, a constructor is not a built-in feature like in C++ or other object-oriented languages. However, you can simulate constructor behavior using functions, typically by initializing variables or allocating memory when creating an object or structure.

For example, you can create an initialization function for a structure in C to mimic a constructor:

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

// Define a structure
struct Person {
    char name[50];
    int age;
};

// Simulate constructor using a function
void initPerson(struct Person *p, const char *name, int age) {
    strcpy(p->name, name);
    p->age = age;
}

int main() {
    struct Person person;
    
    // Call the initialization function (constructor)
    initPerson(&person, "Raghu", 30);
    
    // Display the initialized values
    printf("Name: %s\n", person.name);
    printf("Age: %d\n", person.age);
    
    return 0;
}

In this example, the initPerson function acts like a constructor by initializing the fields of the Person structure.

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

• #include <stdio.h>: This includes the Standard Input/Output library, which provides functions like printf() for printing to the console.
• #include <string.h>: This includes the string handling library, which allows using functions like strcpy() to copy strings.

struct Person {
    char name[50];
    int age;
};

• struct Person: This defines a structure (which is a collection of different types of data grouped together) named Person.
• char name[50];: A character array (string) is used to store the name of the person. It can hold up to 49 characters (with 1 extra for the null terminator \0).
• int age;: An integer to store the age of the person.

void initPerson(struct Person *p, const char *name, int age) {
    strcpy(p->name, name);
    p->age = age;
}

void initPerson: This declares a function initPerson that does not return any value (void).

struct Person *p: The function takes a pointer to a Person structure as its first argument, allowing the function to modify the actual Person object passed to it.

const char *name: This is a constant pointer to a character array (string). It means the function can read from the name string but cannot modify it.

int age: This is an integer argument to pass the age of the person.

strcpy(p->name, name);: This uses the strcpy() function from <string.h> to copy the string name into the name field of the Person structure.

The -> operator is used because p is a pointer, and this is how you access the structure’s fields via a pointer.

p->age = age;: This directly assigns the integer age to the age field of the Person structure.

int main() {
    struct Person person;

int main(): This is the entry point of the program where execution starts.

struct Person person;: This declares a variable person of type struct Person. Memory is allocated for this structure to hold the name and age.

initPerson(&person, "Raghu", 30);

initPerson(&person, "John Doe", 30);: This calls the initPerson function and passes a pointer to person (using the & address-of operator), the string "John Doe", and the integer 30. The function initializes the name and age fields of the person structure.

printf("Name: %s\n", person.name);
printf("Age: %d\n", person.age);

printf("Name: %s\n", person.name);: This prints the name field of the person structure using the %s format specifier (which is used for strings).

printf("Age: %d\n", person.age);: This prints the age field of the person structure using the %d format specifier (which is used for integers).

return 0;

return 0;: This signals that the program has successfully completed. The return value of 0 typically indicates success.