xcode - 如何使用While循环来防止Xcode中随机数中的相同数字？

Question

我希望它不断生成不同的随机数。如何使用 While 语句？

int randomnumber = (arc4random() % 188)+1; 

if ([myArray containsObject:[NSNumber numberWithInt:randomnumber]])
{
    NSLog(@"Yes, they are the same");
    randomnumber = (arc4random() % 188)+1;
}
else
{
    NSLog(@"No, they are not the same");
        }
[myArray addObject:[NSNumber numberWithInt:randomnumber]];

Answer 1

也许是这样的。它循环直到找到不在数组中的数字。

int randomnumber = (arc4random() % 188)+1; 

while ([myArray containsObject:[NSNumber numberWithInt:randomnumber]])
{
    NSLog(@"Yes, they are the same");
    randomnumber = (arc4random() % 188)+1;
}

[myArray addObject:[NSNumber numberWithInt:randomnumber]];

如果您需要大量随机数，您可以将整个事情放入另一个循环中，该循环会根据您需要的不同数字运行尽可能多的轮次。

Answer 2

NSMutableSet 不允许重复。

    NSMutableSet * numberWithSet = [[NSMutableSet alloc]initWithCapacity:20]

    while ([numberWithSet count] < 20 ) {

        NSNumber * randomNumber = [NSNumber numberWithInt:(arc4random() % 23 + 1)];

        [numberWithSet addObject:randomNumber];

    }

        NSLog(@"numberWithSet : %@ \n\n",numberWithSet);

    [numberWithSet release];

    `arc4random() % 22 + 1` will give you numbers between 1 and 22 including both of them but not 23.