NSMutableArray *array = [[NSMutableArray alloc]initWithObjects:@"0", @"1",@"2",@"3",@"4",@"5",@"6",@"7",@"8",@"9",nil];
for (int i = 0;
i< 4;
i++)
{
int arc = arc4random() % 10;
NSString *num = [array objectAtIndex:arc];
[array removeObjectAtIndex:arc];
【----------|从数组中随机取出4个不重复的数字】 }
