Help with Cocoa

I'm trying to finish my second program that's not a tutorial. I'm getting some warnings that I don't understand. I wonder if you could help me. The app takes an input from a text field and outputs the factors and the prime factors into different text fields.

I have 2 arrays, facArray and pfacArray.
Here I'm trying to add integer 'x' into facArray. Whats wrong?

Code:

[facArray addObject:(@"%d", x)];

XCode says: "ACFactor.m:22: warning: passing argument 1 of 'addObject:' makes pointer from integer without a cast"

Here I'm trying to print facArray to a text box:

Code:

[factors setStringValue:(@"%@", facArray)];

XCode says: "ACFactor.m:25: warning: passing argument 1 of 'setStringValue:' from incompatible pointer type"

I have two more like that only with the other array.

Lastly I'm if the input is a prime number I have this:

Code:

[primeFactors setStringValue:(@"%d is a prime number. Please choose another number.", a)];

And this error: "ACFactor.m:47: warning: passing argument 1 of 'setStringValue:' makes pointer from integer without a cast"

Thanks for any help.