Question

For Example:

array[2]={1,2};
myInt=5;

if (array[myInt-6]==2)
   cout << true << endl;
else
   cout << false << endl;

The referenced value in the array in the if statement is clearly out of bounds. When I compile and run this I get false outputted which makes sense as the condition is not true, but I’m wondering why theres no error outputted.

Answer 1

Because undefined behavior is undefined. Anything can happen, including appearing to work.

A diagnostic isn’t required of the compiler nor the runtime. You have to take care of bound checking by yourself.