Question

This is Python programming to develop a multithread program. Please follow the step below.

1. You need to develop a multithread program in Python to simulate a checkout in supermarket. The process of simulation will last for T1 seconds. You do not need to consider thread safety.

2. An integer sequence t is used to record the remaining waiting time for each customer.

3. One thread which runs every one second is used to simulate the processing of the checkout. (a) Reduce the remaining processing time of the first customer by one. (b) Remove the first customer if his remaining processing time reaches zero. (c) Clean the screen and show the new remaining processing time.

4. Another thread is used to generate one new customer every T2 seconds. (a) The new customer will leave the supermarket if he or she needs to join a queue with more than R customers. (b) The processing time for the new customer is a random integer in [Tmin; Tmax)

5. An example program run is shown as follows.

Checkout: 3 12 45 5 61, after one second, we have:

Checkout: 2 12 45 5 61, after one second, we have:

Checkout: 1 12 45 5 61 22, after one second, we have:

Checkout: 12 45 5 61 22, after one second, we have:

Checkout: 11 45 5 61 22

Answer 1

//Include the needed header files
#include <stdio.h>
#include <stdlib.h>
#include <pthread.h>
#include <unistd.h>

//Declare N as constant
#define N 5

//Declare R as constant
#define R 6

//Declare T1 as constant
#define T1 60

//Declare T2 as constant
#define T2 3

//Declare TMIN as constant
#define TMIN 20

//Declare TMAX as constant
#define TMAX 30

//Declare the array t[N][R]
int t[N][R];

//Declare the array n[N]
int n[N];

//Method definition
void function1(void parameter)
{
//Declare the needed variables
int count = 0, index1, index2;

//Loop
while(count<T1)
{
//Increment counter
count++;

//Loop
for(index1=0;index1<N;index1++)
{
//Check condition
if(n[index1]>0)
{
//Check condition
if(t[index1][0]==0)
{
//Decrement
n[index1]--;

//Loop
for(index2=0;index2<n[index1];index2++)
{
//Update
t[index1][index2]=t[index1][index2+1];

//Update
t[index1][n[index1]]=0;
}
}

//Otherwise
else

//Decrement
t[index1][0]--;
}
}

//Output for every checkout every customers time
for(index1=0;index1<N;index1++)
{
//Print
printf("checkout %d :",index1);

//Loop
for(index2=0;index2<R;index2++)
{
//Check condition
if(t[index1][index2]!=0)

//Print
printf("%d ",t[index1][index2]);
}

//Print
printf("customers %d ",n[index1]);

//Print new line
printf(" ");
}

//Delay
sleep(1);

//Clear
system("clear");
}

//Stop
exit(1);
}

//Method definition
void function2(void parameter)
{
//Declare the needed variables
int index1, index2, minValue, place;

//Loop
while(1)
{
//Initialize
minValue=n[0];
place=0;

//Loop
for ( index1 = 0 ; index1 < N ; index1++ )
{
//Condition
if ( n[index1] < minValue )
{
//Update
minValue = n[index1];
place = index1;
}
}

//Compute
t[place][minValue]= rand()%(TMAX - TMIN)+TMIN;

//Increment
n[place]++;

//Delay
sleep(T2);
}
}

//Driver
int main()
{
//Create thread variables
pthread_t td1,td2;

//Declare a variable
int retValue;

//Start thread1
retValue=pthread_create(&td1,NULL,function1,NULL);

//Check condition
if(retValue!=0)
{
//Print
printf("error");

//Exit
exit(1);
}

//Start thread2
retValue=pthread_create(&td2,NULL,function2,NULL);

//Check condition
if(retValue!=0)
{
//Print
printf("error");

//Exit
exit(1);
}

//Thread join
pthread_join(td1,NULL);

//Thread join
pthread_join(td2,NULL);

//Stop
return 0;
}