Assigning value in while loop condition

Question

I found this piece of code on Wikipedia.

#include 

int main(void)
{
  int c;

  while (c = getchar(), c != EOF && c != \'x\')
  {
           


        

Answer 1

The comma operator is a binary operator that evaluates its first operand and discards the result, it then evaluates the second operand and returns this value.

It is also a "sequence point", which means that all side effects will be calculated before the next part of the code is executed.