CODEWITHSUNDEEP
c++recursion
otch92
otch92

Reputation: 1

My program unexpectedly finishes when I call return in a recursive function

I have this recursive function which traverses a binary tree and returns the value of the node when it gets to a node that is leaf but my program unexpectedly finishes at the return call. Here is my code:

string decodeFile(int cha, ibitstream& input, HuffmanNode* encodingTree, HuffmanNode*& root, string& result) {
  if(root->isLeaf()) {
    char value = root->character;
    string temp(1,value);
    cout << temp << endl;
    return temp;
  } else {
    if(cha == 0) root = root->zero;
    if(cha == 1) root = root->one;
    decodeFile(input.readBit(), input, encodingTree, root, result);
  }
}

so I console out to check what is happening and at that point it returns a value but when i go to the main function to cout it returns nothing.

Upvotes: 0

Views: 98

Answers (2)

Nemanja Boric
Nemanja Boric

Reputation: 22157

Well, you're not returning value from the recursive call to the caller:

string decodeFile(int cha, ibitstream& input, HuffmanNode* encodingTree, HuffmanNode*& root, string& result) {
if(root->isLeaf()) {
    char value = root->character;
    string temp(1,value);
    cout << temp << endl;
    return temp;
} else {
    if(cha == 0) root = root->zero;
    if(cha == 1) root = root->one;
    // do calculation and return result!
    return decodeFile(input.readBit(), input, encodingTree, root, result);
}

its a string type so i return the value as a string temp

Imagine that you're entering your code from main function and that you're going into else branch in the first call of decodeFile which will call decodeFile again:

main -> decodeFile -> decodeFile

Now, the second decodeFile is returning value with return temp, but the first decodeFile is not returning anything to the main function (as it is exiting after call to decodeFile):

main (NO RETURN)  decodeFile <- decodeFile

In order to avoid these kind of errors, listen Riot and add additional warning flags to your compiler.

Upvotes: 3

Riot
Riot

Reputation: 16706

Your function is failing to return anything in the else portion of the branch.

If you're using gcc, you can get your compiler to warn you about such cases using the -Wreturn-type or -Wall options.

Upvotes: 0

Related Questions