c++ SJF algorithm , infinite loop

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C++

simulate

So,as a part of a project, i am trying to create a SJF scheduling simulation using C++. i am posting a part of my code which i found online and implemented in mine.
For some reason the loop is infinite and i cant figure out why. Also if someone could explain what t and w variables are would be very helpfull.

waittime[1]=0;
w=w+ data[1];
t=w;
S[1]=0;

while(w<tt)>
{

    i=2;
    while(i<= nPages)
    {
        if(S[i]==1 && arrival[i]<=t)
        {
            waittime[i]=w;
            cout<<"WaitTime"<<i<<"="<<waittime[i];
            S[i]=0;
            w=w+data[i];
            t=w;
            i=2;
        }
        else
            i++;
    }
}

//calculating average weighting Time
for(i=1;i<=nPages;i++)
    sumWaitTime=sumWaitTime+(waittime[i] - arrival[i]);
AverageWaitTime=sumWaitTime/nPages;
cout<<"Total Weighting Time="<<sumWaitTime<<"";
cout<<"Average Weighting Time="<<AverageWaitTime<<"";

Additional information: All S[i] and waittime[i] have been initialized as 1(meaning True) and 0 respectively. Arrival[i] and Data[i] (burst times) have values(from poisson and exponential distributions) and finaly Tt is the total time ( sum of all burst times)

Thanks in advance, Dimitris

source of code http://www.planet-source-code.com/vb/scripts/ShowCode.asp?txtCodeId=11825&lngWId=3