hi i started learnin c++ and i just cant understand this code:

// arrays example

#include <iostream.h>

int billy [] = {1, 2, 3, 4, 5};

int n, result=0;

int main ()

{

loop1: cout << "input a number smaller than 5 \n ";

cin >> n;

if (n>=5)

goto loop1;

for( n ; n<5 ; n++ )

{

result += billy[n];

}

cout << result;

return 0;

}

i even made the arrays very small to try to understand it but i just cant!! heres my understanding..

i input a n say like 2

then in the formula result += billy[n] means..? result += result + billy[3]??

this is weird the outcome are as follows when i enter the numbers

0=15

1=14

2=12

3=9

4=5

please shed some light for this newbie