Question

This code gives me a seg fault, but when I change the x-- to --x it prints correctly.

Are not they the same????

int main()
{    
    myFunc(5); 
    return 0;
}

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

Answer 1

No they are not the same.

The difference between x-- and --x is whether the returned value is before or after the decrement.

In myFunc(x--), x-- returns the old value. So myFunc() gets called repeatability with the same value -> infinite recursion.

In myFunc(--x), --x returns the new value. So myFunc() gets called with a decreasing number each time -> no infinite recursion.

---

It will be easier to see this if you moved your printf to the start of the function call:

void myFunc (int x) {  
    printf("%d, ", x);

    if (x > 0) {
        myFunc(x--);

    }
    else
        return;
}

Output: (when called with 10)

10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, ...