scanf() function

Question

Why I have different result when I have use the " , " symbol between two formats specifier in the scanf() function ?

scanf("%d %d", & a, &b) => return right result

scanf("%d , %d", &a, &b) => return something delirium.

Answer 1

If you put the comma there, you also have to put it into the input, together with space. I tried it and it worked
In the question you have also one space before the comma -> it needs to be in what you input