Question

Now, I know that this is a simple question for MacOS, but when I compile a code with ‘arc4random % n’ in it, I just get an error log in Terminal saying:

main.m:9: error: ‘arc4random’ undeclared (first use in this function)
main.m:9: error: (Each undeclared identifier is reported only once
main.m:9: error: for each function it appears in.)

and I use:

gcc `gnustep-config --objc-flags` -lgnustep-base main.m -o main

to compile it

and here’s my code (if it helps) :

#import <Foundation/Foundation.h>

int main (int argc, const char * argv[])
{
        NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];

        int number, guess;

    number = arc4random() % 101;

    while (!guess == number) {  
        NSLog (@"Please guess a number between 1 and 100");
        scanf ("%i", &guess);

        if  (guess < number) {
            NSLog (@"Sorry, guessed too low!");
        }

        else if (guess > number) {
            NSLog (@"Sorry, guessed too high!");
            }
    }

        NSLog (@"You guessed correct!");

        [pool drain];
        return 0;
}

Answer 1

You may consider using clang instead of gcc

Use

clang -fno-objc-arc main.m -framework Foundation -o main

Also I’d use arc4random_uniform(101) instead of arc4random() % 101, since the former is bias free.