Hello dear Community,
I discovered weird behaviour when using std::cout. At line 75 I invoke the function "traverse(...)". traverse(...) will invoke "visit(int)". visit(int) will just print the int-parameter that is applied to the function.
I created a breakpoint on line 75 to investigate how the preorder on an binary-tree is working and discovered weird behaviour when it comes to the console-output of visit(int).
If I'm using at line 101, within the visit(int)-function:
std::cout << std::endl << "Node: " << i << std::endl;
It's normally printed. But if I will use:
std::cout << std::endl << "Node: " << i;
The zero (0) will not be printed if the visit(int)-function is executed first. Whilst examining the the debugger I observed the variable i that is applied to visit(i). From the beginning: i = 0, NO console output is printed, then the second run of visit(i) is executed with i = 2. But instead printing the 2, the 0 will be printed.
It seems that the missing
<< std::endl
will lead to weird behavior of the whole line.
Does anybody expected same issues? Just try it.
/*
* Project: Traversing of a binary-tree with the preorder (recursive).
* Author: https://github.com/OtenMoten
*
* A binary-tree is suitable for managing efficient data.
* "Preorder" means the algorithm will first check the root, then
* the left sub-tree and finally the right sub-tree.
*
* Just check out https://stackoverflow.com/questions/2130416/what-are-the-applications-of-binary-trees
* to read about the use-cases of binary-trees.
*
* Coding Standard:
* "a" = address variable (i.e. int& aTest;)
* "i" = normal variable (i.e. int iTest;)
* "p" = pointer variable (i.e. int* pTest;)
* "x" = array (i.e. int xTest[10][5];)
*
* Created on 6. Februar 2019, 23:05
*/
#include <cstdlib>
#include <stdio.h>
#include <iostream>
using namespace std;
constexpr int MAX_COLUMNS(4);
void print(int, int[][MAX_COLUMNS]);
void visit(int);
void height(int, int[][MAX_COLUMNS], int&, int&);
void traverse(int, int[][MAX_COLUMNS], int[]);
void out(int[]);
int main(int argc, char** argv) {
constexpr int iCoutRows_Alpha = 9;
constexpr int iCoutRows_Beta = 11;
int aCurrentHeight = 0;
int aFinalHeight = 1;
int xDataFromTree[100] = {0};
// Father - Left Son - Right Son - Data
int xTreeAlpha[iCoutRows_Alpha][MAX_COLUMNS] = {
{0, 5, 3, 0}, // Node 0
{4, 0, 0, 101}, // Node 1
{7, 0, 0, 102}, // Node 2
{0, 0, 0, 103}, // Node 3
{5, 1, 7, 0}, // Node 4
{0, 6, 4, 0}, // Node 5
{5, 0, 0, 104}, // Node 6
{4, 8, 2, 0}, // Node 7
{7, 0, 0, 105} // Node 8
};
int xTreeBeta[iCoutRows_Beta][MAX_COLUMNS] = {
{0, 2, 1, 0}, // Node 0
{0, 4, 8, 0}, // Node 1
{0, 5, 3, 0}, // Node 2
{2, 9, 6, 0}, // Node 3
{1, 10, 7, 0}, // Node 4
{2, 0, 0, 107}, // Node 5
{3, 0, 0, 102}, // Node 6
{4, 0, 0, 104}, // Node 7
{1, 0, 0, 101}, // Node 8
{3, 0, 0, 105}, // Node 9
{4, 0, 0, 103} // Node 10
};
std::cout << std::endl;
std::cout << "Preorder-Traversing" << std::endl;
print(iCoutRows_Beta, xTreeBeta);
std::cout << std::endl;
traverse(0, xTreeBeta, xDataFromTree); // Start with the root, node 0.
std::cout << std::endl << std::endl;
height(0, xTreeBeta, aCurrentHeight, aFinalHeight);
std::cout << "Height of the binary-tree = " << aFinalHeight;
out(xDataFromTree);
return 0;
};
void print(int iCountRows, int b[][MAX_COLUMNS]) {
int iColumnA = 0;
int iColumnB = 1;
int iColumnC = 2;
int iColumnD = 3;
std::cout << std::endl;
std::cout << "Binary-tree:";
for (int iii = 0; iii < iCountRows; iii++) {
std::cout << std::endl;
std::cout << "Father - Left - Right - Data";
printf("\n%3d %7d %7d %7d ", b[iii][iColumnA], b[iii][iColumnB], b[iii][iColumnC], b[iii][iColumnD]);
};
};
void visit(int i) {
std::cout << std::endl << "Node: " << i << std::endl;
};
void height(int root, int xBinaryTree[][4], int &aCurrentHeight, int &aFinalHeight) {
aCurrentHeight++; // "aCurrentHeight" is the current layer of the node.
if (aCurrentHeight > aFinalHeight) aFinalHeight = aCurrentHeight; // The final height is >= the current height.
if (xBinaryTree[root][1] != 0) // The current node is NOT a leaf!
{
height(xBinaryTree[root][1], xBinaryTree, aCurrentHeight, aFinalHeight); // Get the height of the left sub-tree.
height(xBinaryTree[root][2], xBinaryTree, aCurrentHeight, aFinalHeight); // Get the height of the right sub-tree.
};
aCurrentHeight--;
};
void traverse(int i, int baum[][4], int inhalt[]) {
int az;
visit(i);
if (baum[i][1] != 0) // aktueller Knoten ist kein Blatt
{
traverse(baum[i][1], baum, inhalt); //linken Sohn
traverse(baum[i][2], baum, inhalt); //rechten Sohn
} else {
az = inhalt[0]; // aktueller Knoten ist Blatt
inhalt[az + 1] = baum[i][3];
inhalt[0] = az + 1;
};
};
void out(int xInputArray[]) {
std::cout << std::endl;
std::cout << "Count of leafs with data = " << xInputArray[0];
std::cout << std::endl << std::endl;
std::cout << "Data is:";
for (int i = 1; i < xInputArray[0] + 1; i++) {
std::cout << std::endl;
std::cout << xInputArray[i];
};
};
Kind regards Oten
