typedef struct {
    
    CGFloat r;
    CGFloat g;
    CGFloat b;
    
}TestStruct;

@interface ViewController ()

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    
    NSMutableArray *array = [NSMutableArray array];
    //保存
    for (int i = 0; i < 5; ++i) {
        TestStruct s;
        s.b = i;
        s.g = 1.0;
        s.r = 2.0f;
        NSValue *value = nil;
        value = [NSValue valueWithBytes:&s objCType:@encode(TestStruct)];
        [array addObject:value];
    }
    //读取
    for(NSValue *value in array){
        TestStruct s;
        [value getValue:&s];
        NSLog(@"%f",s.b);
    }
}