feat: project 1

project1/phase2/phase2.c

@@ -0,0 +1,130 @@
+#include <errno.h>
+#include <pthread.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+#include <unistd.h>
+
+#define NUM_ACCOUNTS 8
+#define NUM_TELLERS 128
+#define TRANSACTIONS_PER_TELLER 1000
+
+// Monetary value in cents
+typedef long currency;
+
+void sprintf_currency(char *buffer, currency c) {
+  if (c < 0) {
+    c = -c;
+    sprintf(buffer, "-");
+    buffer += sizeof(char);
+  }
+  sprintf(buffer, "$%ld.%.2ld", c / 100, c % 100);
+}
+
+void printf_currency(currency c) {
+  if (c < 0) {
+    c = -c;
+    printf("-");
+  }
+  printf("$%ld.%.2ld", c / 100, c % 100);
+}
+
+// Accounts (shared resource)
+typedef struct account {
+  int account_id;
+  currency balance;
+  int transaction_count;
+  pthread_mutex_t lock; // Account access mutex
+} account;
+
+void deposit(account *acc, currency amount) {
+  pthread_mutex_lock(&acc->lock);
+  // CRITICAL SECTION BEGIN
+  acc->balance += amount;
+  acc->transaction_count++;
+  // CRITICAL SECTION END
+  pthread_mutex_unlock(&acc->lock);
+}
+
+// Global account array
+account accounts[NUM_ACCOUNTS];
+
+// Teller threads
+
+pthread_t tellers[NUM_TELLERS];
+
+typedef struct teller_args {
+  int teller_id;
+  currency total;
+} teller_args;
+
+void *teller_thread(void *arg) {
+  teller_args *args = (teller_args *)arg;
+  int id = args->teller_id;
+  currency total = 0;
+
+  unsigned int seed = time(NULL) + pthread_self();
+  for (int i = 0; i < TRANSACTIONS_PER_TELLER; i++) {
+    // Deposit or withdraw random currency amount from $0 to $1000
+    currency random_amount = ((long)rand_r(&seed)) % 100000;
+
+    char *operation;
+    currency random_amount_i = random_amount;
+    if (rand_r(&seed) % 2) {
+      random_amount_i = -random_amount;
+      operation = "Withdrawing";
+    } else {
+      operation = "Depositing";
+    }
+
+    int random_acc = rand_r(&seed) % NUM_ACCOUNTS;
+    deposit(&accounts[random_acc], random_amount_i);
+
+    // Display result of transaction
+    char buffer[8];
+    sprintf_currency(buffer, random_amount);
+    printf("Thread %u: %s %s into account %u\n", id, operation, buffer,
+           random_acc);
+
+    total += random_amount_i;
+  }
+
+  args->total = total;
+  return NULL;
+}
+
+int main() {
+  // Initialize all accounts with 0 balance
+  for (int i = 0; i < NUM_ACCOUNTS; i++) {
+    accounts[i] = (account){.account_id = i, .balance = 0};
+    pthread_mutex_init(&accounts[i].lock, NULL);
+  }
+
+  // Initialize tellers
+  teller_args args[NUM_TELLERS];
+  for (int i = 0; i < NUM_TELLERS; i++) {
+    args[i] = (teller_args){.teller_id = i};
+    pthread_create(&tellers[i], NULL, teller_thread, &args[i]);
+  }
+
+  // Wait for all threads to finish
+  currency expected_total = 0;
+  for (int i = 0; i < NUM_TELLERS; i++) {
+    pthread_join(tellers[i], NULL);
+    expected_total += args[i].total;
+  }
+
+  currency actual_total = 0;
+  for (int i = 0; i < NUM_ACCOUNTS; i++) {
+    actual_total += accounts[i].balance;
+  }
+
+  printf("Total balance: ");
+  printf_currency(actual_total);
+  printf("\nExpected total: ");
+  printf_currency(expected_total);
+  printf("\n");
+
+  return 0;
+}