Common APIs for the STDLIB standard library

How to use:

The code for obtaining an integer between 0 and X-1 by Arc4random () is as follows:

int value = Arc4random ()% x;

The code to get an integer between 1 and X is as follows:

int value = (arc4random ()% x) + 1;

2), ccrandom_0_1 () cocos2d use, range is [0,1]

How to use:

float random = ccrandom_0_1 () * 5; [0,5] Ccrandom_0_1 () value range is [0,1]

3), random () set seed when initialization is required

How to use:

Srandom ((unsigned int) time (time_t *) NULL); When initializing, set the seed to be OK.

RAND () is not actually a real pseudo-random number generator, and random () is relatively good, but not ideal. Fortunately, there are other options on the iphone. Personally I prefer arc4random () because it is a true pseudo-random algorithm, and is twice times the range of rand ().

-(Float)Randomfloatbetween:(Float)NUM1 andlargerfloat:(Float)Num2
{
IntStartval=Num1*10000;
IntEndval=Num2*10000; 
 
     int Randomvalue =+ (arc4random () % (endval - startval< Span class= "pun"));  
     float a =  Randomvalue; 
     return (a /10000.0 
 }            /span>                

Common APIs for the Stdlib standard library