I recently started teaching my nephew how to program. Since he wants to learn to program iPhone’s and iPad’s, it made a lot of sense to introduce him to Objective C right away. One of my favorite first programs to write is a math program. To do that, you need be able to read input from the user. In C you would do something like:

char name[80];
printf("What is your name? ");
scanf("%s", name);
printf("Hello %s\n",name);

In Objective C you read using a NSFileHandle using the fileHandleWithStandardInput. The below code will read a single line (i.e.: read until the user presses Return) and will trim the CR that is at the end of the string. You’ll notice I used printf instead of NSLog since I wanted to keep the cursor on the same line as the prompt:

printf("What's your name?");
NSFileHandle *input = [NSFileHandle fileHandleWithStandardInput];
NSData *inputData = [NSData dataWithData:[input availableData]];
NSString *inputString = [[NSString alloc] initWithData:inputData
    encoding:NSUTF8StringEncoding];
inputString = [inputString stringByTrimmingCharactersInSet:
    [NSCharacterSet whitespaceAndNewlineCharacterSet]];
printf("Hello %s.\n",[inputString UTF8String]);