Loops Practise

#include <iostream.h>
#include <conio.h>
int main ()
{
    clrscr ();
    long int last=0;
    cout <<"Enter The Number Till That You Want Sum Of Odd Numbers: ";
    cin >> last;
    long int a=0;
    long int start=1;
    for (int n=start;n<last;n++)
    {
        if (start<=1)
            a++;
        start=start+2;
        a=a+start;
        n=start;
    }
    cout <<"\n Sum Of All Odd Numbers = "<<a;
    getch();
    return 0;
}