CODEWITHSUNDEEP
iphoneobjective-cxcoderandom
sagarkothari
sagarkothari

Reputation: 24810

generating random values in iPhone

I have used rand(). But it gives a specific value even after I restart application.

I have implemented following in my application.

- (void)viewDidLoad {
[super viewDidLoad];
int x,y;

x=random() % 480; y=random() % 300;

lblT.center=CGPointMake(x,y); // my label lblT
}

Try to implement in your application, and launch application. After restarting application, you will find that label will be on specific value.

Upvotes: 2

Views: 10968

Answers (6)

Alexey Ryabinin
Alexey Ryabinin

Reputation: 61

use this code, only for Integer random values

#define random(min,max) ((arc4random() % (max-min+1)) + min)

testing

for (int i = 0; i < 500; i++) {
    NSLog(@"rand is %d", random(-100,100));
}

Upvotes: 1

gcamp
gcamp

Reputation: 14662

Use the following line before random()

srand(time(NULL));

Upvotes: 8

ASKAPPS
ASKAPPS

Reputation: 17

I would do it like this:

landscape:

- (void)viewDidLoad {
[super viewDidLoad];


int x = arc4random()%480;
int y = arc4random()%320;

lblT.center=CGPointMake(x,y);
}

not landscape:

 - (void)viewDidLoad {
    [super viewDidLoad];


    int x = arc4random()%320;
    int y = arc4random()%480;

    lblT.center=CGPointMake(x,y);
    }

Upvotes: 1

probablyCorey
probablyCorey

Reputation: 2498

Since you are using random() and not rand() you should seed the random generator with this bit of code...

srandomdev();

Upvotes: 1

Dave DeLong
Dave DeLong

Reputation: 243146

arc4random() is a built-in function that does not require seeding (and so therefore does not produce predictable sequences that can be generated by using a seed), and it conveniently returns integers. I never use anything else.

Upvotes: 13

pavium
pavium

Reputation: 15118

Random number generators in software will actually give PSEUDORANDOM sequences of values.

Unless you seed the random number generator with a value from a truly random event, you will always get the same sequence each time you use the software.

I don't know about your software, but it doesn't look like you're seeding the random number generator, Gcamp is probably on the right track.

Upvotes: 2

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