After some thought, I decided to rework in Objective-C and Cocoa in order to get the hang of OS X and possibly the iOS environment. So I decided to make a simple password encrypting program to start off(although I have worked on one application before in Objective-C and Cocoa). In my case of encrypting, I made a program in C that simply worked based off an alogrithm that does multiplying, dividing, modulo division, and addition, if needed, using the ASCII standard(after all, you can sometimes get the value of a character by typecasting it as an integer when printing it to the console). However, my current problem is that how do you manipulate strings within an NSString as in changing the value of the character by numbers? I know that you can't use a char variable to grab a specific character from an NSString and I don't think you can get an NSString to grab characters from a char variable. I also know that you can't use a char to grab parts from an NSTextField, so the only way to grab a string from an NSTextField is to use an NSString as far as I know. So how could I do this?