[SOLVED] Why doesn't comma operator seem to work between a "if" statement and an "else" statement in my code?

Why doesn't comma operator seem to work between a "if" statement and an "else" statement in my code?

I know a statement like the following (commas in place of semicolons) looks odd:

 if(a < b) printf("Hello\n"), a+=5, b/=5, printf("%d,%d", a, b);

But it works perfectly fine and I had read that it's because comma here acts as a sequence point. I can understand this. But I just fail to understand why the following fails then, where I have used a else as well:

  if(a < b) printf("Hi\n"), else printf("Bye\n"), a+=5, b/=5, printf("%d,%d", a, b);

It gives the error expected expression before 'else'.

Why does the second statement gives error?In the first statement, we saw that comma acts as a sequence point.Then why it doesn't act so before else?What's special about the second case that causes error?Here's my full program:

#include <stdio.h>

int main(void)
{
    int a=30, b=45;

    //if(a < b) printf("Hello\n"), a+=5, b/=5, printf("%d,%d", a, b); // Works well
    if(a < b) printf("Hi\n"), else printf("Bye\n"), a+=5, b/=5, printf("%d,%d", a, b);
}

Solution

The comma operator expects an expression and the else part of an if else construct isn’t an expression. Thus a comma followed by the keyword else is a syntax error.