RunTime应用--对私有变量进行更改

#pragma mark --改变私有变量
-(void)chageVar{
model *a = [[model alloc]init];
[a printIn];//打印name

unsigned int count = 0;
Ivar *ivars = class_copyIvarList([a class], &count);
Ivar name = ivars[1];
object_setIvar(a, name, @"上海");
NSLog(@"对name进行更改\n");
[a printIn];
}