130 lines
3 KiB
C
130 lines
3 KiB
C
#include <errno.h>
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#include <pthread.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <time.h>
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#include <unistd.h>
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#define NUM_ACCOUNTS 8
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#define NUM_TELLERS 128
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#define TRANSACTIONS_PER_TELLER 1000
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// Monetary value in cents
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typedef long currency;
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void sprintf_currency(char *buffer, currency c) {
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if (c < 0) {
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c = -c;
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sprintf(buffer, "-");
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buffer += sizeof(char);
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}
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sprintf(buffer, "$%ld.%.2ld", c / 100, c % 100);
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}
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void printf_currency(currency c) {
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if (c < 0) {
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c = -c;
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printf("-");
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}
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printf("$%ld.%.2ld", c / 100, c % 100);
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}
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// Accounts (shared resource)
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typedef struct account {
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int account_id;
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currency balance;
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int transaction_count;
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pthread_mutex_t lock; // Account access mutex
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} account;
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void deposit(account *acc, currency amount) {
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pthread_mutex_lock(&acc->lock);
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// CRITICAL SECTION BEGIN
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acc->balance += amount;
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acc->transaction_count++;
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// CRITICAL SECTION END
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pthread_mutex_unlock(&acc->lock);
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}
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// Global account array
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account accounts[NUM_ACCOUNTS];
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// Teller threads
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pthread_t tellers[NUM_TELLERS];
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typedef struct teller_args {
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int teller_id;
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currency total;
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} teller_args;
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void *teller_thread(void *arg) {
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teller_args *args = (teller_args *)arg;
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int id = args->teller_id;
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currency total = 0;
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unsigned int seed = time(NULL) + pthread_self();
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for (int i = 0; i < TRANSACTIONS_PER_TELLER; i++) {
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// Deposit or withdraw random currency amount from $0 to $1000
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currency random_amount = ((long)rand_r(&seed)) % 100000;
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char *operation;
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currency random_amount_i = random_amount;
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if (rand_r(&seed) % 2) {
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random_amount_i = -random_amount;
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operation = "Withdrawing";
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} else {
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operation = "Depositing";
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}
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int random_acc = rand_r(&seed) % NUM_ACCOUNTS;
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deposit(&accounts[random_acc], random_amount_i);
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// Display result of transaction
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char buffer[8];
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sprintf_currency(buffer, random_amount);
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printf("Thread %u: %s %s into account %u\n", id, operation, buffer,
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random_acc);
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total += random_amount_i;
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}
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args->total = total;
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return NULL;
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}
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int main() {
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// Initialize all accounts with 0 balance
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for (int i = 0; i < NUM_ACCOUNTS; i++) {
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accounts[i] = (account){.account_id = i, .balance = 0};
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pthread_mutex_init(&accounts[i].lock, NULL);
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}
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// Initialize tellers
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teller_args args[NUM_TELLERS];
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for (int i = 0; i < NUM_TELLERS; i++) {
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args[i] = (teller_args){.teller_id = i};
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pthread_create(&tellers[i], NULL, teller_thread, &args[i]);
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}
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// Wait for all threads to finish
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currency expected_total = 0;
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for (int i = 0; i < NUM_TELLERS; i++) {
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pthread_join(tellers[i], NULL);
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expected_total += args[i].total;
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}
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currency actual_total = 0;
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for (int i = 0; i < NUM_ACCOUNTS; i++) {
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actual_total += accounts[i].balance;
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}
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printf("Total balance: ");
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printf_currency(actual_total);
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printf("\nExpected total: ");
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printf_currency(expected_total);
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printf("\n");
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return 0;
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}
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