Generate Random Numbers with Fixed Digits Length?

Question

I am generating Random Number with

int randomID = arc4random() % 3000;

But I want to generate random number with atleast 4 digits. like 1000, 2400, 1122

I want to know the code for Objective C.

@DharmbirChoudhary I want to send it messages to server it will not kept in cache it will be clean. — Amir iDev, Sep 27 '13 at 13:29
This question has been asked so many times. Please check this answer http://stackoverflow.com/questions/160890/generating-random-numbers-in-objective-c/7082580#7082580. You better use a solution with `arc4random_uniform` as your upper bound is 9999 or 2999. — marsei, Sep 27 '13 at 13:41

lanbo · Accepted Answer · 2013-09-27T13:36:01.090

24

Please try

generate numbers :1000~9999

int randomID = arc4random() % 9000 + 1000;

generate numbers :1000~2999

int randomID = arc4random() % 2000 + 1000;

edited Sep 27 '13 at 13:36

answered Sep 27 '13 at 13:24

lanbo

1,678
12
12

Suppose if random number is 3000 and add 1000 then it will be 4000. So user wanna less then 3000. So it may be problem in future. – Dharmbir Singh Sep 27 '13 at 13:33
3

if it wants less than 3000 and 4 digits then you can use int randomID = arc4random() % 2000 + 1000; – lanbo Sep 27 '13 at 13:35

score 8 · Answer 2 · edited Nov 03 '18 at 06:26

At least four digits, right?

So you need something with flexibility:

-(NSString *)getRandomPINString:(NSInteger)length
{
    NSMutableString *returnString = [NSMutableString stringWithCapacity:length];

    NSString *numbers = @"0123456789";

    // First number cannot be 0
    [returnString appendFormat:@"%C", [numbers characterAtIndex:(arc4random() % ([numbers length]-1))+1]];

    for (int i = 1; i < length; i++)
    {
        [returnString appendFormat:@"%C", [numbers characterAtIndex:arc4random() % [numbers length]]];
    }

    return returnString;
}

and use it like so:

NSString *newPINString = [self getRandomPINString:4];

Generate Random Numbers with Fixed Digits Length?

2 Answers2

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