Condition checking: if(x==0) vs. if(!x)

Question

What\'s the differences of if(x==0) vs. if(!x)? Or are they always equivalent? And for different C++ build-in types of x:

Answer 1

Take into account what are you going to process

If it is a boolean, the results are pretty clear:

if (!false)   // If false TRUE
if (false==0) // If false TRUE

If it is an integer, pay attention to the ! condition

if (0==0) // Unexpected behaviors are missing..

if (!-1) // False
if (! 0) // True
if (! 1) // False

For chars both conditions give me the same results:

if (! ' ')  // nothing
if (' '==0) // nothing

if (! 'z')  // nothing
if ('z'==0) // nothing