Objective-c @ encode keyword

1. If you want to know the specific data type in nsnumber, the @ encode keyword will be used.

Use @ encode (Atype) to return the C string of this type, represented by const char. For example, @ encode (INT) returns I; @ encode (float) returns F.

Then, the const char * returned by the objctype method in nsvalue is okay with the comparison above. Use strcmp to compare the size by ASCII value.

int a = 10;NSNumber *number = [NSNumber numberWithInt:a];if (strcmp([number objCType], @encode(int)) == 0) {      int result = [number intValue];      NSLog(@"%d", result);}

2. The data type of objective-C, or even the meta type of a custom type, function, or method, can all use ASCII encoding.

        NSLog(@"int        : %s", @encode(int));        NSLog(@"float      : %s", @encode(float));        NSLog(@"float *    : %s", @encode(float*));        NSLog(@"char       : %s", @encode(char));        NSLog(@"char *     : %s", @encode(char *));        NSLog(@"BOOL       : %s", @encode(BOOL));        NSLog(@"void       : %s", @encode(void));        NSLog(@"void *     : %s", @encode(void *));                NSLog(@"NSObject * : %s", @encode(NSObject *));        NSLog(@"NSObject   : %s", @encode(NSObject));        NSLog(@"[NSObject] : %s", @encode(typeof([NSObject class])));        NSLog(@"NSError ** : %s", @encode(typeof(NSError **)));                int intArray[5] = {1, 2, 3, 4, 5};        NSLog(@"int[]      : %s", @encode(typeof(intArray)));                float floatArray[3] = {0.1f, 0.2f, 0.3f};        NSLog(@"float[]    : %s", @encode(typeof(floatArray)));                typedef struct _struct {            short a;            long long b;            unsigned long long c;        } Struct;        NSLog(@"struct     : %s", @encode(typeof(Struct)));

The result is:

int        : ifloat      : ffloat *    : ^fchar       : cchar *     : *BOOL       : cvoid       : vvoid *     : ^vNSObject * : @NSObject   : {NSObject=#}[NSObject] : #NSError ** : ^@int[]      : [5i]float[]    : [3f]struct     : {_struct=sqQ}

Reference: http://nshipster.com/type-encodings/