C Programming MACROS

Question

Can someone explain how the output is derived for the second printf statement.
I have not understood how the value of x changed to 13 instead of 10. Detailed step by step explanation please.

 

    #include <stdio.h>
    #define f(a,b) a+b
    #define g(a,b) f(a,b)/f(a,b)
     
    int main(){
        int x=4;
        g(x,x+1);
        printf("%d\n",x);
        x=g(x,x+1);
        printf("%d",x);
        return 0;
    }

Comments

$g(a,b) : f(a,b) / f(a,b)$

$g(a,b): a + b / a + b$

$a = x , b = x+1$

$x + x + 1 / x + x + 1$

$x + x + (1/x) + x + 1$                   // $"/"$ has higher precedence than $'+'$ , it will be executed first

$4 + 4 + (1/4) + 4 + 1$

$4 + 4 + 0 + 4 + 1$

$13$

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Thanks a lot bro.