main.m

gistfile1.m

#import <Foundation/Foundation.h>
#import <stdio.h>

@interface RGB : NSObject
{
    unsigned char red, green, blue;
}
- (id)initWithRed:(int)r green:(int)g blue:(int)b;
- (id)blendColor:(RGB *)color;
- (void)print;
@end

static unsigned char roundUChar(int v){
    if(v < 0) return 0;
    if(v > 255) return 255;
    return (unsigned char)v;
}

@implementation RGB
- (id)initWithRed:(int)r green:(int)g blue:(int)b{
    if((self = [super init]) != nil){
        red = roundUChar(r);
        green = roundUChar(g);
        blue = roundUChar(b);
    }
    return self;
}
- (id)blendColor:(RGB *)color{
    red = ((unsigned int)red + color->red) /2;
    green = ((unsigned int)green + color->green) /2;
    blue = ((unsigned int)blue + color->blue) /2;
    return self;
}
- (void)print{
    printf("(%d, %d, %d)\n", red, green, blue);
}
@end

int main(void){
    @autoreleasepool{
        RGB *u, *w;
        u = [[RGB alloc] initWithRed:255 green:127 blue:127];
        w = [[RGB alloc] initWithRed:0 green:127 blue:64];
        [u print];
        [w print];
        [[u blendColor:w] print];
        return 0;
    }
}