iPhone Strange problem with NSString

Question

Hi, I have following code which is called numerous times:

NSString *Final =  [ NSString stringWithFormat:@"%@%@%@%@.%@%@", str1, str2, str3, str4, str5, str6];

Every once a while Final string is set to nil, while str1 ... to str6 are perfectly valid string (I have verified in debugger)!

I had this code originally, but every once a while Final was also an invalid pointer

NSString *Final =  [ [NSString alloc] initWithFormat:@"%@%@%@%@.%@%@", str1, str2, str3, str4, str5, str6];
...
[Final release];

I am absolutely puzzled. What could this be?

Basically I am collecting values from various edit boxes, form a string from these values and eventually convert it to the number.

Thanks!

Answer 1

this is a clumsy alternative. If your line does not work, try this:

NSString * finalstr = str1;
finalstr = [finalstr stringByAppendingString:str2];
finalstr = [finalstr stringByAppendingString:str3];
finalstr = [finalstr stringByAppendingString:str4];
finalstr = [finalstr stringByAppendingString:str5];
finalstr = [finalstr stringByAppendingString:str6];

by the way, i used to avoid those commonly used reserved words to be my variable names (though final is not a reserved word by objective-c).