OC -- 练习

/*
1.已知某学校的教学课程内容安排如下：
Tom CoreJava
John Oracle
Susan Oracle
Jerry JDBC
Jim Unix
Kevin JSP
Lucy JSP

1）使用一个字典，以老师的名字作为键，老师教授的课程作为值，表示上述课程安排
2）增加了一位新老师Allen 教JDBC
3）Lucy 改为教 CoreJava
4）遍历字典，输出所有老师及老师教授的课程
5）利用字典，输出所有JSP的老师
*/

main.m

//1.
NSDictionary *teach = @{@"Tom":@"CoreJava",
                                       @"John":@"Oracle",
                                       @"Susan":@"Oracle",
                                       @"Jerry":@"JDBC",
                                       @"Jim":@"Unix",
                                       @"Kevin":@"JSP",
                                       @"Lucy":@"JSP"};
                                     
//2.
NSMutableDictionary *dic = [NSMutableDictionary dictionaryWithDictionary:teach];

[dic setObject:@"JDBC" forKey:@"Allen"];

//3.
[dic setObject:@"CoreJava" forKey:@"Lucy"];

//4.
//获取所有的键
NSArray *allkeys = [dic allKeys];

//遍历 键 数组
for (NSString *key in allkeys)
{
  NSLog(@"%@ - %@",key,[dic objectForKey:key]);
}

//5.
NSLog(@"教JSP的老师有:");
for (NSString *key in allkeys)
{
  NSString *lesson = [dic objectForKey:key]

//判断两个字符串[内容]是否相等
if([lesson isEqualToString:@"JSP"])
{
  NSLog(@"%@ - %@",key,[dic objectForKey:key]);
}
}