Emon Emoni Emon Emoni - 1 year ago 89
Objective-C Question

Recursive Factorial

#import <Foundation/Foundation.h>

@interface Factorial : NSObject
+(int) factorial:(int) n;

@implementation Factorial

+(int) factorial:(int)n
if (n==0) {
return 1;
return [self factorial:n]*[self factorial:n-1];


int main (int argc, const char * argv[])
int i = [Factorial factorial:5];
NSLog(@"%d", i);
return 0;

what is the problem with this code?? i am new in objective-c (i am from c background)
Or, i am getting wrong concept about objective c??

(Compiler generating ..)
GNU gdb 6.3.50-20050815 (Apple version gdb-1708) (Mon Aug 8 20:32:45 UTC 2011)
Copyright 2004 Free Software Foundation, Inc.
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This GDB was configured as "x86_64-apple-darwin".tty /dev/ttys002
sharedlibrary apply-load-rules all
[Switching to process 1413 thread 0x0]
warning: Unable to restore previously selected frame.

and getting stuck at line +(int) factorial:(int) n at the @implementation resulting EXC_BAD_ACESS.


Answer Source

I am not familiar with ObjC, but lines:

+(int) factorial:(int)n
    return [self factorial:n]*[self factorial:n-1];
    //                      ^

look suspicious for me. It means that for n != 0 you will get endless recursion and face stack overflow :-)

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