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iosuibuttonarc4random

Arc4random error: "Invalid operands to binary expression ('float' and 'float')"

I want to create a button at random position in certain view. I searched and read some SO topics however I couldn't find the solution for my problem.

Here is my code:

UIButton *button1 = [UIButton buttonWithType:UIButtonTypeCustom];
CGRect buttonRect = button1.frame;
buttonRect.size = CGSizeMake(100, 100);
button1.frame = buttonRect;

[self.arr addObject:button1];

int r = ([button1 frame].size.width)/2;

int x = r + (arc4random() % (self.view.frame.size.width - button1.frame.size.width));
int y = r + (arc4random() % (self.view.frame.size.height - button1.frame.size.height));
//ERROR:Invalid operands to binary expression ('float' and 'float')

[button1 setCenter:CGPointMake(x, y)];
Solution

  • mod (%) doesn't work on floats.

    int x = r + (arc4random() % (int)(self.view.frame.size.width - button1.frame.size.width));
int y = r + (arc4random() % (int)(self.view.frame.size.height - button1.frame.size.height));

    As an additional note, arc4random() % … is not recommended.

    Here is the preferred method:

    int x = r + arc4random_uniform(self.view.frame.size.width - button1.frame.size.width);
int y = r + arc4random_uniform(self.view.frame.size.height - button1.frame.size.height);