Question

I would like to wipe a NSString object in my code (replace every characters by 0).

To do that I tried this :

NSString *myString;
for (int i=0; i<[myString length]; i++) 
{
myString[i] = 0;
}

But it doesn’t compile : “Incompatible types in assignment” at line myString[i] = 0;

I understand, but I can’t use function stringByReplacingOccurancesOfString because it creates a new object and I would like to replace characters in my first object.

Any help ?

Answer 1

NSString is immutable, meaning that you can not change its contents once its created. You have NSMutableString for that purpose.

Also, you can not access the characters in a NSString or NSMutableString with this syntax:

myString[i] = 0;

NSStrings and NSMutableStrings are objects and you work with objects by sending messages to them. For instance, you have characterAtIndex: method that returns the character at the given index, or NSMutableString‘s replaceOccurrencesOfString:withString:options:range: that replaces all occurrences of a given string in a given range with another given string.