static NSString * const testString = @"google";
//表示testString這個指針不能被修改,如若對testString賦值則會報錯:testString = @"hello";編譯器會報錯
?
static?NSString?const?*testString =?@"google";
//表示testString指向對對象不能被修改,testString指針本身可以被修改:此時 testString = @"hello"; 編譯器不會報錯
?
http://stackoverflow.com/questions/6828831/sending-const-nsstring-to-parameter-of-type-nsstring-discards-qualifier