void rec(int x)
{
    if(x>0)
        rec(x--);
    printf("%d",x);
}

int main()
{
    rec(4);
    _getch();

} /*This doesn't work. And shows a stackoverflow */

void rec(int x)
{
    if(x>0)
        rec(--x);
    printf("%d",x);
}

int main()
{
    rec(4);
    _getch();

} /*This gives a proper output as expected*/
/*The output is 00123*/

void rec(int x) {
    if (x>0)
        rec(x--);
    printf("%d",x);
}

int a, b;
a = b = 1;

printf("--a: %d b--: %dn", --a, b--); // Output is --a: 0 b--: 1