The while keyword is used to apply condition for execution of the loop. It is control flow statement, in which a condition is specified, which may be either true or false at a time, and allows the execution accordingly.
while(1) is as similar as writing any integer other than 0. It allows the execution of given loop infinite number of times, without any break. However, this increases the usage of CPU.
while(0) tells that the specified condition will always remain false, resulting in no execution of code.