Why different results in c while using assignment operator in C

Question

I am getting different results in the following code
int main( )
{
int k = 35 ;
printf ( "\n%d %d", k == 35, k = 50) ;
return 0;
}
It prints 0 50
int main( )
{
int k = 35 ;
printf ( "\n%d", k == 35) ;
return 0;
}
While it prints 1
Why is it 0 in first case and 1 in second
https://code.sololearn.com/cEXWmBmB5B2A/?ref=app

Answer 1

You can not know in which order your function arguments will be evaluated - undefined behaviour.

That's why we don't use AND change the same value in one statement.

Seems k=50 is done first, so after that k==35 obviously would return false.