Adding this to any class conforming to NSObject protocol will print out the instance's properties in a friendly format when passed to `+ (NSString *)stringWithFormat:`

gistfile1.m

#import <objc/runtime.h>

- (NSString *)description{
    
    NSMutableString *objectDescription = [NSMutableString stringWithFormat:@"<%@: %p ",NSStringFromClass([self class]),self];
    
    unsigned int outCount, i;
    
    objc_property_t *properties = class_copyPropertyList([self class], &outCount);
    
    for (i = 0; i < outCount; i++) {
        
        objc_property_t property = properties[i];
        
        id propertyValue = [self valueForKey:[NSString stringWithUTF8String:property_getName(property)]];
        
        [objectDescription appendFormat:@"%@:%@ ",[NSString stringWithUTF8String:property_getName(property)],[propertyValue description]];
        
    }

    free(properties);
    
    [objectDescription appendString:@">"];
    
    return objectDescription;
    
}