Printf with reference variable

Assuming this code

int main(){
    int i=0, j=0;

    cout << i << " " << f1(&i,&j) << " " << j << endl;

    cout << i << " " << j << endl;
}

int f1(int *i, int *j){
    *i = 20;
    *j = 30;

    return 10;
}

The result is

20 10 0
20 30

I am puzzled as to why j would be 0 while i correctly shows 20