I'm trying to get a parameter with this function...
public static int subsumer(string id,int acc,SqlConnection connection)
{
acc++;
SqlCommand cercas = new SqlCommand("select * from common_relation where id_source ='" + id + "' AND type='@' ", connection);
SqlDataReader leggsyn = null;
leggsyn = cercas.ExecuteReader();
int f = 0;
while (leggsyn.Read())
{
f= subsumer(leggsyn["id_target"].ToString(),acc,connection);
if (acc <= f)
{
acc = f;
}
}
//siamo arrivati alla fine
return acc-1;
}
each cycle the parameter acc
will increment and debugging i see that in my case it reach value 3, but in the final recursion i get always 0...i can't get it...thank you all
You need to pass acc by reference. Ie use: public static int subsumer(string id,ref int acc,SqlConnection connection) {
By returning acc - 1
, you are decrementing f
returned by your recursive call and I don't think that's what you expect.
public static int subsumer(string id,int acc,SqlConnection connection)
{
SqlCommand cercas = new SqlCommand("select * from common_relation where id_source ='" + id + "' AND type='@' ", connection);
SqlDataReader leggsyn = null;
leggsyn = cercas.ExecuteReader();
int f = 0;
while (leggsyn.Read())
{
f= subsumer(leggsyn["id_target"].ToString(),acc + 1,connection);
if (acc <= f)
{
acc = f;
}
}
//siamo arrivati alla fine
return acc;
}
On a side note, querying recursively isn't a good design choice. Querying recursively with readers open for each call on the stack is even worse. Not using query parmeters is also a bad thing.
该方法在开始时递增,在结束时递减,因此,看来您总是会以acc的初始调用值(在您的情况下为0)结束。
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