The first one asserts that the calculator instance object is not null, i.e. it exists.

第一个宣称这个计数器实例对象不是空，就像它实际存在一样。

youdao

If the string to be searched is not found and neither argument is null, the result is 0.

如果没有找到搜索字符串，并且参数都不为空，则所得的结果是0。

youdao

If the host is not defined already, the output is null.

如果还没有定义该主机，那么输出将为空。

youdao

If the stock is not produced, then the shorting transaction will be null and void and the broker will have to purchase the stock, says Jamie Selway, managing director at White Cap Trading.

FORBES: Magazine Article

Translation, if one were to start with a pre-trial null hypothesis probability of 50% (reflecting equipoise, an ethical prerequisite for randomizing patients), the post-trial null hypothesis probability would still be 9%, which is not sufficient to change my practice.

FORBES: Chelation For Heart Disease: Not What You Have Read

As a result, Botha has turned to the courts in an attempt to have his Bulls contract declared null and void, while Sarfu has not confirmed whether his Springbok contract is part of his court application.

BBC: Strike threat to Springbok tour