In cocos 3:
Writing:
cocos2d::UserDefault::getInstance()->setStringForKey( “InsertStrKeyNameHere”, stringValue );
cocos2d::UserDefault::getInstance()->setIntegerForKey( “InsertNrKeyNameHere”, numericValue );
Reading:
stringValue = cocos2d::UserDefault::getInstance()->getStringForKey( “InsertStrKeyNameHere” );
numericValue = cocos2d::UserDefault::getInstance()->getIntegerForKey( “InsertNrKeyNameHere” );
EDIT: The include is: #include “cocos2d.h”
Good luck!