iOS different data types are stored in variable arrays

1. We all know that the data type that needs to be placed in the NSMutableArray variable array is a class, but the ordinary data type is not a class. We can use the NSNumber class to package it into a class (ie, implement it in the form of an object) for storage.
  

    NSMutableArray *array = [[NSMutableArray alloc] init];
    BOOL    isYes = NO;
    int     a = 10;
    long    longA = 10;
    double  doubleA = 10.123;
    char    charStr = 'c';
    [array addObject:[NSNumber numberWithBool:isYes]];
    [array addObject:[NSNumber numberWithInt:a]];
    [array addObject:[NSNumber numberWithDouble:doubleA]];
    [array addObject:[NSNumber numberWithLong:longA]];
    [array addObject:[NSNumber numberWithChar:charStr]];

 

After encapsulating the basic type data into NSNumber, you can retrieve it through the following instance method

- (char) charValue;
- (int) intValue;
- (float) floatValue;
- (BOOL) boolValue;
- (NSString *) stringValue;

2. Give a chestnut

例如 NSNumber *num = [NSNumber numberWithInt:100];

NSInteger integer = [num intValue];