Question

I want my while loop to stop whenever the user enters 1 or 2. If anything else is entered then it should repeat. I tried putting an exclamation mark before the variable name and using an equality sign. I tried using a single or operator.

The petId variable is getting the right numbers — I see the NSLog()s for “Dog” and “Cat”. Why is the loop looping despite having a 1 or 2 entered?

int petId;
while(petId != 1 || petId!=2)
        {
            NSLog(@"%d",petId);
            NSLog(@"Would you like to create a dog or a cat?\n1.Dog 2.Cat");
            //Scan user input
            scanf("%i",&petId);
            if(petId == 1)
            {
                NSLog(@"Dog");
            }
            else if(petId==2)
            {
                NSLog(@"Cat");
            }
            else
            {
                NSLog(@"Invalid Entry");
            }
        }

Answer 1

You probably made a mistake in the boolean operators:
Replace

while(petId != 1 || petId!=2)

With

while(petId != 1 && petId!=2)