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

typedef struct {
    long long cents;
} Amount;

Amount* amount_create(long long cents) {
    Amount* a = (Amount*)malloc(sizeof(Amount));
    a->cents = cents;
    return a;
}

Amount* amount_from_string(const char* str) {
    long long cents = 0;
    int decimal_pos = -1;
    int len = strlen(str);
    for (int i = 0; i < len; i++) {
        if (str[i] >= '0' && str[i] <= '9') {
            cents = cents * 10 + (str[i] - '0');
            if (decimal_pos >= 0) decimal_pos++;
        } else if (str[i] == '.') {
            decimal_pos = 0;
        }
    }
    while (decimal_pos < 2) {
        cents *= 10;
        decimal_pos++;
    }
    Amount* a = (Amount*)malloc(sizeof(Amount));
    a->cents = cents;
    return a;
}

char* amount_to_string(Amount* a) {
    char* buf = (char*)malloc(32);
    long long abs_cents = a->cents >= 0 ? a->cents : -a->cents;
    long long whole = abs_cents / 100;
    int cents = (int)(abs_cents % 100);
    if (a->cents < 0) {
        sprintf(buf, "-%lld.%02d", whole, cents);
    } else {
        sprintf(buf, "%lld.%02d", whole, cents);
    }
    return buf;
}

Amount* amount_add(Amount* a, Amount* b) {
    Amount* result = (Amount*)malloc(sizeof(Amount));
    result->cents = a->cents + b->cents;
    return result;
}

Amount* amount_subtract(Amount* a, Amount* b) {
    Amount* result = (Amount*)malloc(sizeof(Amount));
    result->cents = a->cents - b->cents;
    return result;
}

Amount* amount_multiply(Amount* a, double factor) {
    Amount* result = (Amount*)malloc(sizeof(Amount));
    result->cents = (long long)(a->cents * factor);
    return result;
}

int amount_compare(Amount* a, Amount* b) {
    if (a->cents > b->cents) return 1;
    if (a->cents < b->cents) return -1;
    return 0;
}

long long amount_to_cents(Amount* a) { return a->cents; }
void amount_free(Amount* a) { free(a); }