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);