105 lines
2.5 KiB
C
105 lines
2.5 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 5
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#define NUM_TRANSFERS 5
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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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// Global account array
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account accounts[NUM_ACCOUNTS];
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// Threads
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pthread_t transfers[NUM_TRANSFERS];
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typedef struct transfer_args {
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int transfer_id;
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account *from;
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account *to;
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currency amount;
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} transfer_args;
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void *transfer_thread(void *arg) {
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transfer_args *args = (transfer_args *)arg;
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int id = args->transfer_id;
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account *from = args->from;
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account *to = args->to;
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currency amount = args->amount;
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pthread_mutex_lock(&from->lock);
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printf("Thread %u: Locked account %d\n", id, from->account_id);
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usleep(100); // Delay to account for other threads
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pthread_mutex_lock(&to->lock);
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printf("Thread %u: Locked account %d\n", id, to->account_id);
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from->balance -= amount;
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to->balance += amount;
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from->transaction_count++;
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to->transaction_count++;
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printf("Thread %u: Unlocked account %u\n", id, from->account_id);
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printf("Thread %u: Unlocked account %u\n", id, to->account_id);
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pthread_mutex_unlock(&to->lock);
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pthread_mutex_unlock(&from->lock);
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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 transfers
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transfer_args args[NUM_TRANSFERS];
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for (int i = 0; i < NUM_TRANSFERS; i++) {
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args[i] = (transfer_args){.transfer_id = i,
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.from = &accounts[i % NUM_ACCOUNTS],
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.to = &accounts[(i + 1) % NUM_ACCOUNTS],
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.amount = 1000};
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pthread_create(&transfers[i], NULL, transfer_thread, &args[i]);
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}
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// Wait for all threads to finish
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for (int i = 0; i < NUM_TRANSFERS; i++) {
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pthread_join(transfers[i], NULL);
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}
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return 0;
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}
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