What is the difference between
if (false == <condition>)
and
if (!<condition>)
and
unless (<condition>)
What is the difference between
while (false == <condition>)
and
while (!<condition>)
and
until (<condition>)
Why isn’t unless and until in all programming languages?
Thank you for your help.
>Solution :
if (false == <condition>)
and
if (!<condition>)
and
unless (<condition>)
Logically, they are all equivalent.
Likewise:
while (false == <condition>)
and
while (!<condition>)
and
until (<condition>)
Logically they are equivalent. Except syntactically, until() might be used at the end of a loop and while() at the beginning of a loop.
Although logically they are equivalent, some programming languages provide them (unless, until) for readability.
And you might want to take a look of this to trace back their first usage in programming language.