How to pass the address of structure as an argument to function in C language?

Passing the address of a structure as an argument to a function allows the function to access and modify the original structure through a pointer. This technique is memory-efficient and enables direct manipulation of structure members.

Syntax

return_type function_name(struct structure_name *pointer_variable);

Key Points

• The address of the structure is passed as an argument to the function.

• It is collected in a pointer to structure in function header.

Advantages

• No wastage of memory as there is no need of creating a copy again

• No need of returning the values back as the function can access indirectly the entire structure and work on it.

Example

Here's how to pass the address of a structure to a function −

#include <stdio.h>

struct date {
    int day;
    int mon;
    int yr;
};

void display(struct date *dt) {
    printf("day = %d<br>", dt->day);
    printf("month = %d<br>", dt->mon);
    printf("Year = %d<br>", dt->yr);
}

int main() {
    struct date d = {02, 01, 2010};
    display(&d);
    return 0;
}

day = 2
month = 1
Year = 2010

How It Works

• The &d passes the address of structure d to the function.
• The parameter struct date *dt receives this address as a pointer.
• The arrow operator -> is used to access structure members through the pointer.

Conclusion

Passing structure addresses to functions is an efficient method that saves memory and allows direct manipulation of structure data. This approach is particularly useful for large structures where copying would be expensive.