feat: project 1

project1/phase1/phase1.c

@@ -0,0 +1,107 @@
+#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 100
+
+// Monetary value in cents
+typedef long currency;
+
+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;
+} account;
+
+// 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++) {
+    printf("Thread %u: ", id);
+    // Deposit or withdraw random currency amount from $0 to $1000
+    currency random_amount = ((long)rand_r(&seed)) % 100000;
+    if (rand_r(&seed) % 2) {
+      printf("Withdrawing ");
+      printf_currency(random_amount);
+      random_amount = -random_amount;
+    } else {
+      printf("Depositing ");
+      printf_currency(random_amount);
+    }
+
+    int random_acc = rand_r(&seed) % NUM_ACCOUNTS;
+    accounts[random_acc].balance += random_amount;
+    accounts[random_acc].transaction_count++;
+
+    printf(" into account %u\n", random_acc);
+
+    total += random_amount;
+  }
+
+  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};
+  }
+
+  // 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;
+}