Thread: Would anyone please explain me this logic ?

Code:

int main()
 
{
 
int i=0, j=0, NUM=3;
 
for(i=-NUM; i<=NUM; i++)
 
{
 
for(j=-NUM; j<=NUM; j++)
 
{
 
if( abs(i)+abs(j)<=NUM) // Change this condition
 
 { cout<<"*"; }
 
else { cout<<" ";}
 
}
 
cout<<endl;
 
}
return 0;
}

I copied this code from crazyprogrammer's blog. If anyone please explain me why the programmer used negative values here?
I have seen many such great programs on internet without any explanation. I would ask the same question to the programmer himself but he has been inactive on Internet since two years and his blog is dead.

One thing that might help, can you post the output of the program?

And if I had to guess negative values, it'd because i and j loop through -num to +num and make a pretty pattern when everything is printed.

Code:

*
***
*****
*******
*****
***
*

the program prints a diamond shape.

thanks laserlight