OC中可变字典和不可变字典

#import <Foundation/Foundation.h>int main(int argc, const char * argv[]){    //不可改变字典，创建后不可改变        NSDictionary * dic = [[NSDictionary alloc]initWithObjectsAndKeys:@"jack",@"name",@"18",@"age", nil];    NSLog(@"%@",dic);    NSDictionary * dic1 = @{@"name":@"jack",@"age":@"18"};    NSLog(@"dic1 %@",dic1);        NSNumber * num = [NSNumber numberWithInt:10];    NSArray * array = @[@"one",@"two",@"three"];    NSDictionary * dic2 = @{@"array":array,                            @"num":num,                            @"dic":dic                            };}

#import <Foundation/Foundation.h>int main(int argc, const char * argv[]){    NSMutableDictionary * dic =    [[NSMutableDictionary alloc]     initWithObjectsAndKeys:@"Tom",@"name" ,@"20",@"age",nil];}