Activity selector (recursive and non recursive) (own)

#include<iostream>
#include<cstring>
using namespace std;

int totalActivity,counterPossible=1,choice;
int startingTime[999999],finishingTime[999999],possibleActivity[999999];

void input();
void sortInput();
void printPossibleActivity();
void RecursiveActivitySelector(int*,int*,int,int);
void GreedyActivitySelector(int*,int*);

int main(void)
{
    input();
    sortInput();
    //RecursiveActivitySelector(startingTime,finishingTime,1,totalActivity);
    //GreedyActivitySelector(startingTime,finishingTime);
    cout<<"Press 1 for Recursive 2 for Non recursive Activity Selector : ";
    cin>>choice;
    if(choice==1)
    {
        RecursiveActivitySelector(startingTime,finishingTime,1,totalActivity);
    }
    else if(choice==2)
    {
        GreedyActivitySelector(startingTime,finishingTime);
    }
    printPossibleActivity();
    return 0;
}

void input()
{
    cout<<"Enter total number of activities : ";
    cin>>totalActivity;
    int i,j,k,start,finish;
    cout<<endl;
    for(i=1; i<=totalActivity; i++)
    {
        cout<<"Enter activity "<<i<<"'s starting and finishing time : ";
        cin>>start>>finish;
        startingTime[i]=start;
        finishingTime[i]=finish;
    }
    cout<<endl;
}
void sortInput()
{
    int i,j,k,l,n=totalActivity,t,tmp;
    for(j = n; j>=2; j--)
    {
        t = 1;
        for(k = 2; k<=j; k++)
        {
            if(finishingTime[t]<finishingTime[k])
            {
                t = k;
            }
            tmp = finishingTime[j];
            finishingTime[j] = finishingTime[t];
            finishingTime[t] = tmp;

            tmp = startingTime[j];
            startingTime[j]=startingTime[t];
            startingTime[t]=tmp;

        }
    }
}

void printPossibleActivity()
{
    int i;
    cout<<endl;
    cout<<"Possible activities : "<<endl;
    cout<<"Activity 1's starting time : "<<startingTime[1]<<" finishing time : "<<finishingTime[1]<<endl;
    for(i=1; possibleActivity[i]!='\0'; i++)
    {
        cout<<"Activity "<<possibleActivity[i]<<"'s starting time : "<<startingTime[possibleActivity[i]]<<" finishing time : "<<finishingTime[possibleActivity[i]]<<endl;
    }
    cout<<endl;
}

void RecursiveActivitySelector(int s[],int f[],int k,int n)
{
    int m = k+1;
    while((m<=n)&&(startingTime[m]<finishingTime[k]))
    {
        m=m+1;
    }
    if(m<=n)
    {
        possibleActivity[counterPossible]=m;
        counterPossible++;
        RecursiveActivitySelector(s,f,m,n);
    }
    else
    {
        return;
    }
}

void GreedyActivitySelector(int s[],int f[])
{
    int n = totalActivity;
    int m,k;
    k=1;
    for(m=2; m<=n; m++)
    {
        if(s[m]>f[k])
        {
            possibleActivity[counterPossible]=m;
            counterPossible++;
            k=m;
        }
    }
}