Object-c初步学习 五

1.常用结构体使用

typedef struct DATE {
? ? int y;
? ? int m;
? ? int d;
} MDate;

?//定义结构体类型
? ? struct DATE {
? ? ? ? int y;
? ? ? ? int m;
? ? ? ? int d;
? ? };
? ? struct DATE d = {2023,1,15};
? ??
? ? MDate d1= {2023,1,1};
? ? NSLog(@"%i",d1.y);
? ??
? ? //NSRange的使用
? ? NSRange ran = NSMakeRange(10, 5);
? ??
? ? NSRange ran2 = {10,8};
? ??
? ? NSRange ran1;
? ? ran1.location = 10;
? ? ran1.length = 1;
? ??
? ? NSString *ranks = NSStringFromRange(ran);
? ? NSLog(@"ran的值为%@",ranks);
? ??
? ? //NSPoint的使用
? ? NSPoint ns = NSMakePoint(10, 10);
? ? NSPoint ns2 = CGPointMake(10, 10);
? ? NSString *nss = NSStringFromPoint(ns);
? ? NSLog(@"nss的值为%@",nss);
? ??
? ? //NSSize的使用
? ? NSSize size = NSMakeSize(100, 100);
? ??
? ? //NSRect的使用
? ? NSRect re = NSMakeRect(10, 10, 100, 100

?2.常用的NSString的创建

    NSString *str1 = @"a string";
    
    NSString *str2 = [[NSString alloc] initWithString:@"a string"];
    [str2 release];
    
    NSString *str3 = [[NSString alloc] initWithUTF8String:"a string"];
    [str3 release];
    
    NSString *str4 = [[NSString alloc] initWithFormat:@"test is %i",10];
    [str4 release];
    
    //从文件中读取文本
    NSError *err;
    NSString *str5 = [NSString stringWithContentsOfFile:@"/Users/liusir/Desktop/pdd账号1.txt" encoding:NSUTF8StringEncoding error:&err];
    NSLog(@"file content >> %@",str5);
    NSLog(@"err %@",[err localizedDescription]);
    
    NSURL *nsurl = [NSURL URLWithString:@"file:///Users/liusir/Desktop/pdd账号1.txt"];
    NSString *str6 = [NSString stringWithContentsOfURL:nsurl encoding:NSUTF8StringEncoding error:nil];
    
    //写入字符串到文本
    NSString *str7 = @"123456";
    [str7 writeToFile:@"/Users/liusir/Desktop/test.txt" atomically:YES encoding:NSUTF8StringEncoding error:nil];

3.NSString常用方法的使用

 NSString *str8 = @"age is 30";
    NSString *str9 = [str8 uppercaseString];//转大写
    NSLog(@"%@",str9);
    NSLog(@"%@",[str8 lowercaseString]);//转小写
    NSLog(@"%@",[str8 capitalizedString]);//首字母大写
    
    NSString *str10 = @"123456";
    //比较字符串是否相同
    NSLog(@"%i",[str8 isEqualToString:str10]);
    
    NSComparisonResult result = [str8 compare:str10];
    if(result == NSOrderedSame){
        NSLog(@"same");
    }else if (result == NSOrderedAscending){
        NSLog(@"NSOrderedAscending");
    }else if (result == NSOrderedDescending){
        NSLog(@"NSOrderedDescending");
    }

NSMutableString 可变字符串的使用

 // NSMutableString 可变字符串的使用
    NSMutableString *nsMStr = [NSMutableString stringWithString:@"123"];
    NSLog(@"nsMStr %%@",nsMStr);
    [nsMStr appendString:@"456"];
    NSLog(@"nsMStr change %@",nsMStr);