Category for adding currency indicators to NSStrings

NSString+CurrencyIndicators.m

@interface NSString (CurrencyIndicators)

-(NSString*)stringByAddingCurrencyIndicator:(NSString*)indicatorCode;

@end

@implementation NSString (CurrencyIndicators)

-(NSString*)stringByAddingCurrencyIndicator:(NSString*)indicatorCode
{
    NSString *formatString = nil;
    NSString *prefix = nil;
    NSString *number = nil;
    // Remove any sign from the front of the string
    if ([self hasPrefix:@"+"] || [self hasPrefix:@"-"])
    {
        prefix = [self substringToIndex:1];
        number = [self substringFromIndex:1];
    }
    else
    {
        prefix = @"";
        number = self;
    }
    
    if ([indicatorCode isEqualToString:@"GBX"])
        formatString = @"%@p";
    else if ([indicatorCode isEqualToString:@"GBP"])
        formatString = @"£%@";
    else if ([indicatorCode isEqualToString:@"USD"])
        formatString = @"$%@";
    else if ([indicatorCode isEqualToString:@"EUR"])
        formatString = @"€%@";
    else if ([indicatorCode isEqualToString:@"n/a"])
        return self;
    else
    {
        NSAssert1(NO,@"Unhandled currency indicator %@",indicatorCode);
        return [NSString stringWithFormat:@"%@ %@",self,indicatorCode];
    }
    
    return [prefix stringByAppendingString:[NSString stringWithFormat:formatString,number]];
}

@end