这个Objective-C陈述是什么意思？

Question

I can usually decipher unfamiliar code, given a few minutes, but what is this:

    NSNumber *one = [NSNumber numberWithInt:rand()%60+20];

It's from XYPieChart.

Thanks!

Answer 1

rand() Returns a pseudo-random integral number in the range between 0 and RAND_MAX. see this link

% is modulo operator and finds the remainder of division of one number by another. See this link

rand() % 60 = Number in range 0 to 59

rand()%60+20 = Number in range 20 to 79

NSNumber is a subclass of NSValue that offers a value as any C scalar (numeric) type.

+ (NSNumber *)numberWithInt:(int)value

Above class method of NSNumber creates and returns an NSNumber object containing a given value, treating it as a signed int.

NSNumber *one = [NSNumber numberWithInt:rand()%60+20];

So the above statement is initialising "one" with NSNumber initialised with random integer between 20 to 79.