摘要:
操作符 NULL safe equal. This operator performs an equality comparison like the = operator, but returns 1 rather than NULL if both operands are NULL, and 阅读全文
摘要:
开放封闭原则(Open Closed Principle OCP) Software entities(classes,modules,functions etc) should open for extension ,but close for modification. 什么意思呢? 所谓开放封 阅读全文