Non preemptive sheduling

[pavanbr143]

This is The function i have written to get waiting times of processes
some one please help me to solve this

class NonPreemptive
{
 public:
     int* getWaitingTime(int* process, int* arrivalTime, int* burstTime, int nProcess)
{       
     int ct[5],temp,j;   
     int* wt = (int*)malloc(sizeof(int)* 5);
     wt[0]=0,j=0;
        for(int i=process[j++];i<=nProcess;i++)
   {   
     if((arrivalTime[0]==0)&&(arrivalTime[j]<arrivalTime[j+1])&&(0<burstTime[j]<10))
      {  
       ct[i]=arrivalTime[i]+burstTime[i]+wt[i];
        wt[i+1]=ct[i]-arrivalTime[i+1];
        if((arrivalTime[j+1]+burstTime[j+1])>(arrivalTime[j+2]+burstTime[j+2]))
        int temp=process[j+1];process[j+1]=process[j+2];process[j+2]=temp;
      }
     else return NULL; 
   }return wt;
}
};

I am working on Non preemptive scheduling algorithm.....
My below function needs to written the waiting time of the processes 1,2,3,4,
and below are the 3 test cases needs to be satisfied.
Test case 1:

int proc[] = {1, 2, 3, 4};
		int arrivalTime[] = {0, 2, 4, 5};
		int burstTime[] = {7, 4, 1, 4};

Test case 2:

int proc[] = {1, 2, 3};
		int arrivalTime[] = {0, 4, 8};
		int burstTime[] = {6, 2, 1};

Test case 3:

int proc[] = {1, 2, 3, 4};
		int aTime[] = {2, 0, 4, 5};         
		int bTime[] = {7, 4, 1, 4};

we have given a constraints like below to satisfy:

i) If more than 1 processes have arrived before the completion of current process
then allocation should be done for the process which having min value of
(arrivalTime+burstTime);
ii) Burst time of processes should be between 0<burst time<10;
ii) arrival Time of the first process should be 0;
vi)arrival Times should be in increasing order.
v)if above condition fails then return NULL;

output for above should be:

test case1: {0,6,3,7}
test case2:{0,2,0}
test case3:{NULL}

[StuXYZ]

This code is a mess, and 99% is that it is mixed c and c++ , it has not been set out tidily so neither I nor you know what is going on.

Things to fix:

Why use malloc to allocate memory use int* wt=new int[5]; Then remember to delete that memory. You fail to do that in your code because if you get the the return NULL you will have made a memory leak.

The loop construction: for(int i=process[j++];i<=nProcess;i++) is 100% too complex. There are nProcess and process has n variables
so what about for(int i=0;i<nProcess;i++) So if process[0] is > nProcess you stop that is wrong.

Then further stangeness, j goes to 1 and stays there,so why write arrivalTime[j+1] so why no write arrivalTime[2] .

The next problem is that you write

if ((arrivalTime[j+1]+burstTime[j+1]) > 
		(arrivalTime[j+2]+burstTime[j+2]))
	      int temp=process[j+1];    
	    process[j+1]=process[j+2];
	    process[j+2]=temp;

Unfortunately, you declare temp again, and that MASKS the original temp. e.g consider this

int temp=1;
 if (1<2)
     int temp=4;    
    std::cout<<"Temp == "<<temp<<std::end;;

This piece of code prints 1 it does not print 4.

Finally, why pass nProcess when this routine only can deal with 4 entries.