Question

I tried below code :

NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];


NSString * str1 = @"program";

NSArray * alphabets = [NSArray arrayWithObjects:@"a",@"b",@"c",@"d",@"e",@"f",@"g",@"h",@"i",@"j",@"k",@"l",@"m",@"n",@"o",@"p",@"q",@"r",@"s",@"t",@"u",@"v",@"w",@"x",@"y",@"z",nil];
NSMutableDictionary * alphaToNum = [NSMutableDictionary dictionary];
NSMutableDictionary * numToAlpha = [NSMutableDictionary dictionary];

NSInteger index =0;
int shifter = 5;

for(NSString * character in alphabets){
    index++;
    [alphaToNum setObject:[NSNumber numberWithInteger:index] forKey:character];
    [numToAlpha setObject:character forKey:[NSNumber numberWithInteger:index]];
}

NSRange * rng = {0,0};
NSLog(@"-------");
//NSLog(@"%@" , [str1 substringWithRange:NSMakeRange(1, 1)]);

for(int i=0;i<[str1 length];i++)
{   
    NSString * ss = [str1 substringWithRange:NSMakeRange(i, 1)];
    NSInteger  i = [alphaToNum valueForKey:ss];

    i = (i + 5);
            NSLog(@"%d",i); //last code
}

and this is what I get for the last code

2011-10-24 13:20:08.289 cipher[22732:a0f] 1103808

2011-10-24 13:20:08.290 cipher[22732:a0f] 1101168

2011-10-24 13:20:08.290 cipher[22732:a0f] 1103200

2011-10-24 13:20:08.290 cipher[22732:a0f] 1103616

2011-10-24 13:20:08.291 cipher[22732:a0f] 1103584

or even sometimes

“EXC_BAD_ACCESS”.

which is totally wrong!

Answer 1

NSInteger  i = [alphaToNum valueForKey:ss];

This will return an NSNumber object, not an NSInteger.

Make that line as follows,

NSInteger  i = [[alphaToNum valueForKey:ss] integerValue];

And regarding the crash, we can answer only after looking at the crash log. That would be more helpful.