Question

It might be the simplest Question, but at this time ,I am not getting any Idea on how to implement this.

Ok, The problem is of how to concatenate two integers.

For Eg: I want to create an integer say 0000 using two different integers 00 and 00. I tried using NSString , but I failed.

My Code is :

                int num1 = 00;
                int num2 = 00;
                NSString *str = [NSString stringWithFormat:@"%d%d",num1,num2];
                int num = [str intValue];
                NSLog(@"num = %d",num); // It Logs 0 but I want 0000.

Does anyone have better Idea ?

EDIT :

Please Note that , I want to use that num to set the tag of textfield. That’s why all the zeros are essential. So my main Problem starts here.

I have one tableview which contains custom cells. This custom cell has more than 10 textfields. Now I want to uniquely identify all the textfields for editing. That’s why the tag for that textfield must be the integer concatenated by two values called rowNumber and textFieldNumber (means which textField out of 10.).

So my question is what I am trying to do is right or not ? And if not then give me some useful solution.

Answer 1

The integer data types (such as int) only store the integer value, not formatting information. Therefore you lose the number of leading zeroes (which do not affect the integer value, i.e., 0, 00, and 0000 are the same integer: zero).

If you wish to retain formatting information, you must store it separately. A simple way is to just store the string itself. Or, if you always want to have the same number of digits, then alter the formatting string:

int num1 = 0;
int num2 = 0;
NSString *str = [NSString stringWithFormat:@"%02d%02d",num1,num2];

After the above code, str will be "0000". However, converting it to int and then logging with %d formatting results in 0 once more (since 0000 and 0 are the same integer).

Edit: For the purpose of generating unique integers for tagging purposes, given a row number (rowNumber) and text field number (textFieldNumber), use a formula like:

tagNumber = rowNumber * 100 + textFieldNumber;

This way the text fields of row 0 will have numbers 0..99, those on row 1 will have 100..199, etc. If more than 100 text fields are required per row, simply multiply by a larger number, like 1000.

In integer arithmetic these values can be converted back to row and field numbers with:

 rowNumber = tagNumber / 100;
 textFieldNumber = tagNumber % 100;