UITextField accepting only one decimal point with max 3 digits before decimal point & max 2 digits after decimal point

Question

I want to restrict UITextField to accept only one decimal point.

Also maximum 3 digits are allowed before decimal point & maximum 2 digits allowed after decimal point.

Please note that minimum digits can be 1 and decimal cant be entered a first.

How can I achieve it?

Answer 1

Thank you so much all folks for helping. By referring those answers I framed below answer.

EDIT

While textfields having e.g. 462. & user touches backspace results to 462 which ideally should result to 46

    - (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
    {
        NSString *strTextField = [textField.text stringByReplacingCharactersInRange:range withString:string];
    // restrict textfield from entering ./0 at first place
    if (strTextField.length > 0) {
        NSString *theCharacterAtIndex0 = [NSString stringWithFormat:@"%c", [strTextField characterAtIndex:0]];
        if ([theCharacterAtIndex0 isEqualToString:@"."] || [theCharacterAtIndex0 isEqualToString:@"0"]) {
            return NO;
        }
    }
    //    NSLog(@"%@ , %@", textField.text, strTextField);

    // automatically add decimal point after 3 digits entered
    if (![textField.text containsString:@"."]) {
        if (strTextField.length == MAX_LENGTH_BeforeDecimal && ![strTextField containsString:@"."]) {
            strTextField = [strTextField stringByAppendingString:@"."];
            textField.text = strTextField;
            return NO;
        }
    }

    // when decimal is deleted
    if ([textField.text containsString:@"."]) {
        if (![strTextField containsString:@"."]) {
            int indeOfdecimal = (int)[textField.text rangeOfString:@"."].location;
            NSString *strBeforeDecimal = [textField.text substringToIndex:indeOfdecimal];
            textField.text = strBeforeDecimal;
        }
    }

    NSArray *separator = [strTextField componentsSeparatedByString:@"."];
    // to restrict textfield to single decimal
    if([separator count] > 2 ) {
        return NO;
    }
    if([separator count] >= 2) {
        // restrict the max digits before & after decimal points
        NSString *sepStr0 = [NSString stringWithFormat:@"%@",[separator objectAtIndex:0]];
        NSString *sepStr1 = [NSString stringWithFormat:@"%@",[separator objectAtIndex:1]];
        if ([sepStr0 length] > 3) {
            return NO;
        }
        if ([sepStr1 length] > 2) {
            return NO;
        }
    }
    return YES;
}