CODEWITHSUNDEEP
objective-ciosxcode
user1491987
user1491987

Reputation: 751

NSArray index 1 beyond bounds for empty array

-(IBAction)someMethod:(UIStepper *)sender{
    int x=sender.value; //This is an integer from 0-8;
    NSLog(@"%f",sender.value);
    NSArray *rpmValues = [[NSArray alloc]initWithObjects:@"a",@"b",@"c",@"d",@"e",@"f",@"g",@"h",@"i", nil];
    if (x<=[rpmValues count]) {

        myLabel.text = [rpmValues objectAtIndex:x];
    }
    NSLog(@"%i",[rpmValues count]);
}

Above is my code, what I want to do is to change UILabel display by changing UIStepper. This is very straight forward. But when I change press the stepper value, it crashes:

*** Terminating app due to uncaught exception 'NSRangeException', reason: '*** -   [__NSArrayM objectAtIndex:]: index 1 beyond bounds for empty array'
*** First throw call stack:

And the [rpmValue count] is 9. I really got confused. Can anyone help me?

Upvotes: 0

Views: 6701

Answers (2)

Tommy
Tommy

Reputation: 100622

At the very least if (x<=[rpmValues count]) should be if (x<[rpmValues count]). Otherwise if you have an array with, say, two entities then you're allowing yourself to access indices 0, 1 and 2 — three possibilities in total.

Is it possible you've set a maximumValue on your stepper of '9' based on similar logic?

Upvotes: 0

WDUK
WDUK

Reputation: 19030

That code seems fine (see my comment on the question); your problem could arise from the use of 

if (x<=[rpmValues count]) {

This will include the count of the array, which exceeds the index range by one. Use

if (x < [rpmValues count]) {

Upvotes: 4

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