/**
 * structs.c
 *
 * Tests structs, dynamic allocation, and arg passing.
 *
 * Compile:  gcc -g -Wall -o structs structs.c
 * Run:      ./structs
 */

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

struct bank_record {
    int id;
    char last_name[100];
    char first_name[100];
    double balance;
};

void increase_balance(struct bank_record * record, float amount) {

    if (amount <= 0) {
        printf("Amount must be greater than 0!");
        return;
    }

    double new_balance = record->balance + amount;

    printf("Increasing the balance of %s, %s (Account %d) from %f to %f\n",
            record->last_name,
            record->first_name,
            record->id,
            record->balance,
            new_balance);

    record->balance += amount;
}

/* We can also pass the struct directly. Note the dot '.' notation */
void print_name(struct bank_record record) {
    printf("Name: %s, %s\n",
            record.last_name,
            record.first_name);
}

/* This version of the print function takes a pointer to a struct instead */
void print_name2(struct bank_record * record) {
    printf("Name: %s, %s\n",
            record->last_name,
            record->first_name);
}

struct bank_record copy_rename(struct bank_record record, char * new_name) {
    strcpy(record.first_name, new_name);
    return record;
}

int main(void) {

    /* Statically allocating a pre-populated struct: */
    struct bank_record record1 = {
        1,
        "Stark",
        "Tony",
        6500000.0
    };

    /* Dynamic allocation: */
    struct bank_record * record2;
    record2 = calloc(8, sizeof(struct bank_record));
    record2->id = 2;
    strcpy(record2->last_name, "Prince");
    strcpy(record2->first_name, "Diana");
    record2->balance = 70000000.0;

    free(record2);

    print_name2(record2);
    print_name2(&record1);
    print_name(*record2);
    printf("id: %d\n", record2->id);

    /* Let's give Tony $10 */
    increase_balance(&record1, 10);

    /* And 5000 to Diana */
    increase_balance(record2, 5000);
    /* (Note the ampersand) */

    /* Now we'll pass these structs by value. Note the pointer dereference */
    print_name(record1);
    print_name(*record2);

    /* Finally, let's return a struct by value. This essentially creates
     * a copy: */
    struct bank_record record3 = copy_rename(record1, "Pepper");
    print_name(record1);
    print_name(record3);

    return EXIT_SUCCESS;
}