使用plist为测验创建随机整数

问题描述

我希望用户单击一个按钮以"a +/- b = c"的形式生成一个十个问题的测验，其中a和b的值从+10到-10，并且是随机的分配了十个问题.同样，问题应在加法和减法之间随机切换.如何正确填充plist文件?如何使用arc4random用随机整数创建十个问题?

I would like to have user click on a button to generate a ten-question quiz in the form of "a +/- b = c" where the values for a and b are from +10 to -10 and are randomly assigned for the ten questions. Also, the questions should randomly switch between addition and subtraction. How do I populate the plist file correctly? How do I use arc4random to create ten questions with random integers?

我认为将问题显示在一个单列选择器中非常方便，用户可以在其中滚动查看问题，也可以只在屏幕上的某个CGPoint处显示文本.

I thought it would be neat to have questions display in a one-column picker where user can scroll through the questions or just have text at a certain CGPoint on screen.

相反，我创建了一个plist，其中包含84个不同的可能问题，并且我希望每次用户单击按钮时从plist中随机选择10个来创建测验.到目前为止，我已经知道了:

Instead, I have created a plist with 84 different possible questions and I want to randomly choose 10 from plist to create the quiz each time a user clicks on button. I have this so far:

NSString *plistFile = [[NSBundle mainBundle] pathForResource:@"global" ofType:@"plist"];
NSDictionary *dict = [NSDictionary dictionaryWithContentsofFile:plistFile];
NSLog(@"%@",[dict objectForKey:@"1"]);
NSLog(@"%@",[dict objectForKey:@"2"]);
NSLog(@"%@",[dict objectForKey:@"3"]);

global是plist的名称，@"1"，@"2"，@"3"等是我放入plist中的84个差异Q的名称.如何从84个NSLog中随机选择10个?

global is the name of plist, @"1", @"2", @"3" etc are the names of the 84 diff Q's I put in plist. How do I randomly choose 10 of the 84 NSLogs?

推荐答案

如果键只是数字，请使用NSArray而不是使用NSDictionary.然后你可以做

Instead of using a NSDictionary, use NSArray if your keys are just numbers. You could then do

NSString *randomString = [array objectAtIndex:(arc4random() % [array count])]; 

选择一个随机元素.

但是，如果它只是随机数的不同组合，我会真的建议不要在plist中查找它.手工写出所有这些组合只是浪费时间.那就是计算机的用途！

However, I would really advice against looking it up in a plist if it's just different combinations of random numbers. Writing out all those combinations by hand is just a waste of time. That's what computers are for!

古老但仍然相关的答案:

Old, but still relevant answer:

生成-10和10之间的随机数:

int a = (arc4random() % 21) - 10;

您还可以创建如下函数:

You could also make a function like this:

int randomIntegerInRange(int min, int max)
{
    int range = max - min + 1;
    return min + arc4random() % range;
}

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