索引-产生好几个随机数

Question

比如现在有五个数字12345，然后随机取出来三个，
我现在的思路是先随机出来一个保存，在随机一个数和第一个比较，一样的话从新随机，不一样的话保存，第三个同理，想着有没有别的办法哈 谢谢了先

Answer 1

-(NSMutableArray*)getRandomNumberArray
{
NSMutableArray *array = [NSMutableArray array];
NSMutableArray *arrayTemp = [NSMutableArray array];
int i;
int firstRandom;
// sum=49;
sum=4;
// NSNumber *temp;
for (i = 0; i<=sum; i++) {
NSNumber *j = [NSNumber numberWithInt:i+1];
// temp = [NSNumber numberWithInt:1];
// j = j+temp;
[array insertObject:j atIndex:i];
}
NSLog(@"%@",array);
firstRandom= self.getRandomFirstNumber;
id valueFirst = [array objectAtIndex:firstRandom];
[array removeObjectAtIndex:firstRandom];
[arrayTemp addObject:valueFirst];
NSLog(@"%@",array);
NSLog(@"%@",arrayTemp);

int secondRandom= self.getRandomFirstNumber;
id valueSecond = [array objectAtIndex:secondRandom];
[array removeObjectAtIndex:secondRandom];
[arrayTemp addObject:valueSecond];
NSLog(@"%@",array);
NSLog(@"%@",arrayTemp);

int thirdRandom= self.getRandomFirstNumber;
id valueThird = [array objectAtIndex:thirdRandom];
[array removeObjectAtIndex:thirdRandom];
[arrayTemp addObject:valueThird];
NSLog(@"%@",array);
NSLog(@"%@",arrayTemp);

int fourthRandom= self.getRandomFirstNumber;
id valueFourth = [array objectAtIndex:fourthRandom];
[array removeObjectAtIndex:fourthRandom];
[arrayTemp addObject:valueFourth];
NSLog(@"%@",array);
NSLog(@"%@",arrayTemp);

NSLog(@"%@",arrayTemp);
// NSLog(@"%i",sum);
// NSLog(@"%@",[arrayTemp objectAtIndex:0]);
return arrayTemp;

}

-(int)getRandomFirstNumber

{
int n = (arc4random() % (sum+1)) +0;
NSLog(@"%i",n);
NSLog(@"%i",sum);
sum--;
NSLog(@"%i",sum);
return n;
}
这是用oc带的代码 意思和上面评论的一样