Thread: Boundary condition

Let's say you read an int and it has to be between 0 and 10, you check the boundaries like this

Code:

if (num < 0 || num > 10)
{
  error();
}

Or you can check the index of an array in a similar manner :-)

>>I wanted to know, what does mean by memory boundary condition checking?
If you have an array

Code:

int a[10];

You check the index to make sure you don't access memory outside of your boundaries, for example, a[i] would go out of bounds if i is 10 or greater, or less than 0, so you might check it like this

Code:

if (i >= 0 && i < 10)
{
  a[i]; /* Safe */
}

Originally posted by Roaring_Tiger
Here are my comments
1. Say I am using this array 100 times in code. Do I need to check the boundary condition every time code accesses the array?

Whenever you use an array, you ALWAYS check your boundries. Never go below zero, and never above SIZE-1.

The easiest way to do this is:

array[ some_var % SIZE ]

Now, this may not give you the right answer in the event your 'some_var' is out of bounds, but it will keep your program from crashing by forcing the value into the bounds of the array.

Quzah.