/*=========================================================*/
  2 /* race.c --- for playing with ECE437 */
  3 /*=========================================================*/
  4 #include <unistd.h>
  5 #include <stdio.h>
  6 #include <stdlib.h>
  7 #include <pthread.h>
  8 struct {int balance[2];} Bank={{100,100}}; //global variable defined
  9 //Sem437* lock = (Sem437*)malloc(sizeof(Sem437));
 10  typedef struct {int S;} Sem437;
 11
 12 void Sem437Init(Sem437* sem, int a)
 13 {
 14     printf("in init function\n");
 15     sem->S = 1;
 16     printf("leaving init function\n");
 17 }
 18
 19 void Sem437P(Sem437* sem)
 20 {
 21     while(&sem->S == 0)
 22         ;
 23     sem->S--;
 24 }
 25
 26 void Sem437V(Sem437* sem)
 27 {
 28     sem->S++;
 29 }
 30 // Sem437* lock;
 31 // Sem437Init(lock, 1);
 32  Sem437* lock = (Sem437*)malloc(sizeof(Sem437));
 33  //int a = 1;
 34  //lock->S = 1;
 35
 36  void* MakeTransactions() { //routine for thread execution
 37  int i, j, tmp1, tmp2, rint; double dummy;
 38
 39  Sem437P(lock);
 40  for (i=0; i < 100; i++) { rint = (rand()%30)-15;
 41  if (((tmp1=Bank.balance[0])+rint)>=0 && ((tmp2=Bank.balance[1])-rint)>=0) {
 42 // Sem437P(lock);
 43  Bank.balance[0] = tmp1 + rint;
 44 // Sem437V(lock);
 45  for (j=0; j < rint*100; j++) {dummy=2.345*8.765/1.234;}
 46 // Sem437P(lock);
 47  Bank.balance[1] = tmp2 - rint;
 48 // Sem437V(lock);
 49 }
 50 }
 51  Sem437V(lock);
 52  return NULL;
 53 }
 54
 55 int main(int argc, char **argv) {
 56 int i; void* voidptr=NULL; pthread_t tid[2];
 57  //Sem437* lock;
 58  //Sem437* lock = (Sem437*)malloc(sizeof(Sem437));
 59  int a = 1;
 60  lock->S = 1;
 61  printf("got to here\n");
 62  //Sem437Init(lock, a);
 63  printf("Lock has value %d \n", lock->S);
 64
 65  srand(getpid());
 66  printf("Init balances A:%d + B:%d ==> %d!\n",
 67  Bank.balance[0],Bank.balance[1],Bank.balance[0]+Bank.balance[1]);
 68  for (i=0; i<2; i++) if (pthread_create(&tid[i],NULL,MakeTransactions, NULL)) {
 69  fprintf(stderr, "Error in thread creating\n"); return(1); }
 70  for (i=0; i<2; i++) if (pthread_join(tid[i], (void*)&voidptr)) {
 71  fprintf(stderr, "Error in thread joining\n"); return(1);}
 72  printf("Let's check the balances A:%d + B:%d ==> %d ?= 200\n",
 73  Bank.balance[0],Bank.balance[1],Bank.balance[0]+Bank.balance[1]);
 74  return 0;
 75 }
 76