Getting a random object from an array, then remove it from array. iphone -

i having problem arrays, want object picked randomly array, , remove , remove other objects specified in "if" statement.

what did..

in .h

nsmutablearray *squares; int s; nsstring *randomn; 

next, in .m

create new array:

-(void) array{     squares = [[nsmutablearray alloc] arraywithobjects: @"a", @"b", @"c", nil]; } 

and choose random object, if properties of "if" met, remove object array, while loop again.

-(void) start{      s=5;      while (s > 0){      //i tried without next line..      randomn = nil;       //also tried next line without ' % [squares count'      randomn = [squares objectatindex:arc4random() % [squares count]];       if (randomn == @"a"){          [squares removeobject: @"a"];          [squares removeobject: @"b"];         s = s - 1;         }       if (randomn == @"b"){          [squares removeobject: @"b"];          [squares removeobject: @"c"];         s = s - 1;         }       if (randomn == @"c"){          [squares removeobject: @"c"];         s = s - 1;         }       else {      s=0;      } } } 

when run app, app stops , quits loop starts.

can please me?

their few issues tripping up:

you're initializing allocated array convenience constructor, should pick 1 of alloc/init pair or convenience constructor itself:

[[nsmutablearray alloc] initwithobjects:...] 

or:

[nsmutablearray arraywithobjects:...] 

your remove lines attempting remove string literals. while array contains string instances contain same values strings you're trying remove, they're not same exact instances of string. need use [stringvar isequaltostring:otherstringvar] compare values instead of references:

if ([randomn isequaltostring:@"a"]) 

instead of:

if (randomn == @"a") 

also, else statement fire every time similar reasons second problem. if use correct string comparisons, logic off if you're trying execute 1 of 4 blocks of code. accomplish that, each of ifs after first needs else, so:

if (/* test 1 */) { } else if (/* test 2 */) { } else if (/* test 3 */) { } else {     // chained else's make 1 block able execute } 

instead of:

if (/* test 1 */) { } if (/* test 2 */) { } if (/* test 3 */) { } else {     // else applies last if! }