starcraft1.c

//--------------------------------------------
// NAME: Veselin Dechev
// CLASS: XIA
// NUMBER: 2
// PROBLEM: #3
// FILE NAME: Starcraft.c (unix file name)
// FILE PURPOSE:
// Synchronising threads with mutex.
// Example with workers and one mine like THE GAME Starcraft.
// ...
//--------------------------------------------

#include <stdio.h>
#include <pthread.h>
#include <stdlib.h>

int NUM_THREADS; //Number of threads

pthread_mutex_t lock; //Mutex
int minerals; //minerals in the mine
int startminerals = 0; //minerals in the Command Center
int soldiers = 0; //soldiers
//--------------------------------------------
// FUNCTION: Getminerals
// Geting the minerals from the mine and allows only one worker to work.
// PARAMETERS:
// ID of the worker
//--------------------------------------------

void* GetMinerals(void* arg){    //Geting the minerals of the mine
    size_t thread_num = (size_t)arg; //get id of the thread
    while(minerals>0){ //when there's a minerals in mine , loop works
        if(soldiers>=20) break;
        pthread_mutex_trylock(&lock); //lock mutex
        printf("SCV %zd is mining\n", thread_num);
        if(minerals>7){
            minerals-=8; //geting the minerals
            startminerals = startminerals + 8; //incrments the minerals in Command Center

        }

        else{ //if the minerals is less than 8, the worker takes the minerals which lefts.
            startminerals = startminerals + minerals;
            minerals-=minerals;
        }
        printf("SCV %zd is transporting minerals\n", thread_num);
            printf( "SCV %zd delivered minerals to 'Command Center 1' %d\n", thread_num, startminerals);
        printf("Remaining minerals: %d\n",minerals);
        pthread_mutex_unlock(&lock); //unlock the mutex

        sleep(2); //simulating when the worker works.
    }
}

int main(int argc, char* argv[]){ //main

    if(argc<2){ //if there's no arguments
        minerals = 5000;
        NUM_THREADS = 5;
    }
    else{ //reading from argument line
        minerals = atoi(argv[1]);
        NUM_THREADS = atoi(argv[2]);
    }

    pthread_t threads[NUM_THREADS]; //creating array from threads
    pthread_mutex_init(&lock, NULL);  //inits the mutex

    size_t i; //counter

    for (i = 1; i <= NUM_THREADS; i++) {
        int error = pthread_create(&threads[i], NULL, GetMinerals, (void*)i); //creating the threads and checks for errors.
        if (error != 0) {
            fprintf(stderr, "Error creating thread %zd: error: %d\n", i, error);
        }
  }
    while(soldiers<20){
        char c; //Reading symbol from keyboard
        scanf("%c",&c);
        if(c=='m'){
            if(startminerals>50){ soldiers++; startminerals-=50;
            printf("You wanna piece of me, boy? %d\n", soldiers);
            }
    else printf("Not enough minerals.\n");
            }
  }
  for (i = 1; i < NUM_THREADS; i++) {
        int error = pthread_join(threads[i], NULL); //joining the threads.
        if (error != 0) {
            fprintf(stderr, "Error joining thread %zd: error: %d\n", i, error);
        }
  }


    pthread_mutex_destroy(&lock); //destroys mutex
  pthread_exit(NULL); //exit from the threads


    return 0; //exit
}
 //creating array from threads
    pthread_mutex_init(&lock, NULL