NSValue和NSNumber和NSString

1

// 使用NSNumber 封装double

        double dNum = 1.3;
        NSNumber *double1 = [NSNumber numberWithDouble:dNum];
        double dNum1 ;
        [double1 getValue:&dNum1];
        NSLog(@"double is %lf", dNum1);
        NSNumber *n = @45;
        NSNumber *n1 = @5.1;
        NSNumber *n2 = @5.2f;
        struct Human human;
        human.age = 100;
        strcpy(human.name, "xiaoming ");
        Human h;

        h.age = 100;

2

// 使用NSValue 封装 int

        int a = 100;
        NSValue *intVal = [NSValue value:&a withObjCType:@encode(int)];
        NSLog(@"intVal = %@", intVal);
        int b = 0;
        [intVal getValue:&b];

        NSLog(@"b = %d", b);

3

NSString *S1 = @"China";
        NSString *S2 = @"China";
        NSString *S3 = [[NSString alloc] initWithString:@"China"];
        NSString *S4 = [[NSString alloc] initWithFormat:@"China"];
        NSLog(@"%d",S1 == S2);
        NSLog(@"%d",S1 == S3);
        NSLog(@"%d",S1 == S4);
        NSString *S5 = [[NSString alloc] init];
        NSString *S6 = [[NSString alloc] init];
        NSLog(@"%d",S5 == S6);

4

// 查找子串
        NSString *str = @"I love China";
        NSString *sub = @"love";
        NSRange range = [str rangeOfString:sub];
        if (range.length !=0 && range.location != NSNotFound && [str containsString:sub]) {
            NSLog(@"loc = %ld, len = %ld",range.location,range.length);
        }

// 字符串拼接
        NSString *string = @"I love";
        NSString *newstring = [string stringByAppendingString:@"I no"];
        NSLog(@"newstring is %@",newstring);
        newstring = [newstring stringByAppendingString:@" too"];
        NSLog(@"newstring is %@",newstring);
    //数字字符串
        NSString *number = @"343";
        int num = number.intValue;
    // 大小写
        NSString *m = @"I Love You";
        NSLog(@"%@",m.uppercaseString);
        NSLog(@"%@",m);
        NSLog(@"%@",m.lowercaseString);
        NSLog(@"%@",m.capitalizedString);
        // 可变字符串 enable change String
        NSMutableString *mulStr = [[NSMutableString alloc] init];
        [mulStr appendString:@"beijing kaifeng ss"];
        NSLog(@"%@",mulStr);
    //insert a String to String
        [mulStr insertString:@"456" atIndex:[mulStr rangeOfString:@"beijing"].location];
         NSLog(@"%@",mulStr);
    // replace a String into String
        [mulStr replaceCharactersInRange:[mulStr rangeOfString:@"beijing"] withString:@"kaifeng"];
         NSLog(@"%@",mulStr);
    // delete a String into String
        [mulStr deleteCharactersInRange:[mulStr rangeOfString:@"ss"]];
        NSLog(@"%@",mulStr);

最后

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