#import <Foundation/Foundation.h>

  @interface Test: NSObject
  @property  NSMutableArray *elements;
  -(void) method;
  @end

  @implementation Test
  @synthesize elements;
  -(void) method{
     elements= [[NSMutableArray alloc] init];
     [elements addObjectsFromArray:@[@"c", @"a", @"b", @"c", @"c", @"d", @"c", @"c", @"e", @"c"]];
     NSLog(@"number of elements initially- %d", elements.count);
     int index= elements.count-1;
     for(id i in [elements reverseObjectEnumerator])
     {
        // static int index= elements.count-1;
        NSLog(@"index- %d", index);
        if([i isEqual:@"c"]){
          [elements removeObjectAtIndex:index];
          NSLog(@"Object in place of removed object- %@, at index- %d", [elements objectAtIndex:index], index);
          NSLog(@"No. of elements left after the removal- %d", elements.count);
        }
       index--;
     }
 }
 @end

 int main()
 {
   Test *test= [[Test alloc] init];
   [test method];
   NSLog(@"elements- %@", test.elements);
 }

cd '~/Desktop/Source Code/'; clang -framework Foundation -w ObjectRemovalInArray.m -o ~/Desktop/Binaries/ObjectRemovalInArray && ~/Desktop/Binaries/ObjectRemovalInArray
  2018-06-18 20:25:25.797 ObjectRemovalInArray[4684:731973] number of elements initially- 10
  2018-06-18 20:25:25.797 ObjectRemovalInArray[4684:731973] index- 9
  2018-06-18 20:25:25.798 ObjectRemovalInArray[4684:731973] *** Terminating app due to uncaught exception 'NSRangeException', reason: '*** -[__NSArrayM objectAtIndex:]: index 9 beyond bounds [0 .. 8]'
  *** First throw call stack:
  (
0   CoreFoundation                      0x00007fff345f632b __exceptionPreprocess + 171
1   libobjc.A.dylib                     0x00007fff5b764c76 objc_exception_throw + 48
2   CoreFoundation                      0x00007fff34637634 _CFThrowFormattedException + 202
3   CoreFoundation                      0x00007fff34515290 __CFStringDecodeByteStream3 + 0
4   ObjectRemovalInArray                0x00000001007dbbaf -[Test method] + 799
5   ObjectRemovalInArray                0x00000001007dbd54 main + 68
6   libdyld.dylib                       0x00007fff5c37e015 start + 1
7   ???                                 0x0000000000000001 0x0 + 1
)
libc++abi.dylib: terminating with uncaught exception of type NSException
Abort trap: 6