Htykuut

I'm doing a quick binary tree program as a homework, but I am getting weird errors that I can't seem to figure out how to fix. Normally I'm programming in C#, and C is just slightly different but different enough for me to get confused.

Here is the code that is giving the error:

void SortArray() {//bubble sorting by float value of 'b'

int flag = 0;



do {

    flag = 1;



    for (int i = 0; i < arraySize - 1; i++)

    {

        if (stubList[i].b > stubList[i + 1].b) {

            Swap(stubList[i], stubList[i + 1]);

            flag = 0;

        }

    }

} while (flag == 0);



printf("Sorted by value of variable 'b'"); _getch(); _getch();

}

And here is the whole script:

#include <conio.h>

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

using namespace std;



struct stub

{

    char crown[51];//some custom name - can be empty

    float b;//comparable value for tree sort

    int c;//limited by maxint

    stub *l;//left node(normally smaller "b" value than this node)

    stub *r;//right node(normally bigger "b" value than this node)

};



stub *stubList[255];//empty list of a stub array with a safe casual amount

int arraySize = 0;



stub *head = NULL;//main stub(first)

stub *latest = NULL;//latest stub



stub *st = NULL;//used for creating and checking



FILE *fs = NULL;

char fileName[255];



int maxint = 20;//for var 'c'



void BTreeNodeToArray(stub *s) {

    stubList[arraySize] = s;



    arraySize++;

}



void Swap(stub &s1, stub &s2) {

    stub temp = s2;



    s1 = s2;

    s2 = temp;

}



int MaxMin(int num) {

    int clampedInt = num;

    if (num < 0) clampedInt = 0;

    else if (num > maxint) clampedInt = maxint;



    return clampedInt;

}



//Create a completely new stub with crown, b, and c variables being filled here

void CreateElement() {

    st = new stub;

    printf("Adding information for node:n");

    printf("Node name: "); gets_s(st->crown);

    printf("n");



    float f;

    printf("Node float value (B): "); scanf_s("%f", &f);

    st->b = f;

    printf("n");



    int d;

    printf("Node integer value (C): "); scanf_s("%d", &d);

    st->c = d;

    printf("n");

    st->c = MaxMin(st->c);



    st->l = NULL;

    st->r = NULL;

}



//creates the very first stub(root/head)

void CreateFirst() {

    printf("First in tree. Adding root node...n");



    CreateElement();

    head = st;

    latest = head;

    BTreeNodeToArray(head);



    printf("Added head stubncrown: %snValue: %fnExtra: %d", head->crown, head->b, head->c);

    getchar();

    getchar();

}



void AddStub() {

    if (head == NULL) {

        CreateFirst();

    }

    else {

        CreateElement();//create newest node

        latest = st;

        st = head;

        int depth = 0;

        while (1) {

            if ((latest->b <= st->b)) {//choose left if true

                printf("Went leftn");

                depth++;

                if (st->l == NULL) {//node free, assign here

                    printf("Node assigned at depth %dn", depth);

                    st->l = latest;

                    BTreeNodeToArray(latest);

                    getchar();

                    getchar();

                    break;

                }

                else {//loop again with next node

                    //printf("New loop (left)n");

                    st = st->l;

                }

            }

            else {//choose right

                printf("Went rightn");

                depth++;

                if (st->r == NULL) {//node free, assign here

                    printf("Node assigned at depth %dn", depth);

                    st->r = latest;

                    BTreeNodeToArray(latest);

                    getchar();

                    getchar();

                    break;

                }

                else {//loop again with next node

                    //printf("New loop (right)n");

                    st = st->r;

                }

            }

        }

    }

}



void ViewArray() {

    for (int i = 0; i < arraySize; i++)

    {

        printf_s("Node [%d]:ntCrown: %sntweight: %fntExta value(0 - %d): %dn", i, stubList[i]->crown, stubList[i]->b, maxint, stubList[i]->c);

    }

    getchar();

}



void SortArray() {//bubble sorting by float value of 'b'

    int flag = 0;



    do {

        flag = 1;



        for (int i = 0; i < arraySize - 1; i++)

        {

            if (stubList[i].b > stubList[i + 1].b) {

                Swap(stubList[i], stubList[i + 1]);

                flag = 0;

            }

        }

    } while (flag == 0);



    printf("Sorted by value of variable 'b'"); _getch(); _getch();

}



void ProcessArray() {

    char c = ' ';

    int found = 0;



    printf("Process with character: n"); c = _getch();



    if (arraySize <= 0) {

        printf("No List!");

        return;

    }



    char chkstr[5];

    for (short i = 0; i < 5; i++)//simple assign to a 'string' 5 times

    {

        chkstr[i] = c;

    }



    for (int i = 0; i < arraySize; i++)

    {

        if (strstr(stubList[i]->crown, chkstr) != NULL) {

            // contains

            printf("B = %f at [%d] n", stubList[i]->b, i);

            found++;

        }

    }



    if (found > 0) {

        printf("---Found: %d with character %c---", found, c);

    }

    else {

        printf("No elements found with '%c'", c);

    }

    getchar();

}



void ExportArray() {

    FILE *fs = NULL;

    char fileName[255];

    errno_t err;



    printf("Save to file as: n"); gets_s(fileName);



    if (strlen(fileName) == 0) {

        printf("Failed to create file. File name empty!");

        _getch();

        _getch();

    }



    err = fopen_s(&fs, fileName, "wb");

    if (err != 0) {

        printf("Failed to create file!!!");

        _getch();

        _getch();

        return;

    }



    for (int i = 0; i < arraySize; i++)

    {

        int written = fwrite(&stubList[i], sizeof(stub), 1, fs);

        //fwrite(&gr[i], sizeof(student), 1, fs);

    }

    int numclosed = _fcloseall();



    printf("Exported to file: %s", fileName);

    getchar();

}



void CleanReset() {//reset all values and release memory (function used for import)

    for (int i = 0; i < arraySize; i++)

    {

        delete stubList[i];

    }



    arraySize = 0;

    st = NULL;

    head = NULL;

    latest = NULL;

}



void ImportArray() {

    FILE *fs = NULL;

    char fname[255];

    errno_t err;



    printf("Open FIle: "); gets_s(fname);



    err = fopen_s(&fs, fname, "rb");

    if (err == 0) {

        CleanReset();



        fseek(fs, 0, SEEK_END);

        long size = ftell(fs);

        arraySize = size / sizeof(stub);//get amount of students saved

        fseek(fs, 0, SEEK_SET);



        int i = 0;



        st = new stub;

        fread_s(&st, sizeof(stub), sizeof(stub), 1, fs);

        stubList[i] = st;

        while (!feof(fs)) {

            i++;

            st = new stub;

            fread_s(&st, sizeof(stub), sizeof(stub), 1, fs);

            stubList[i] = st;

        }



        printf("File data imported. Size: %d", arraySize);

        getchar();

        return;

    }



    printf("Failed to import file!!!");

    getchar();

}



void main()

{

    system("chcp 65001");//use utf8



    char izb = 'i';



    while (izb != '0') {

        system("cls");



        printf_s("1. Add stubn");

        printf_s("2. View Arrayn");

        printf_s("3. Sort Arrayn");

        printf_s("4. Processn");

        printf_s("5. Export array to filen");

        printf_s("6. Import array from filen");

        printf_s("0. Exitnn");



        printf_s("Choose action:n"); izb = _getch();



        switch (izb)

        {

        case '1':

            AddStub();

            break;

        case '2':

            ViewArray();

            break;

        case '3':

            SortArray();

            break;

        case '4':

            ProcessArray();

            break;

        case '5':

            ExportArray();

            break;

        case '6':

            ImportArray();

            break;

        case '0':

            //Exit();

            break;

        }

    }

}

The error is that you want to pass a stub * to a function that wants a stub &. The first one is a pointer, the second one is a reference.

You have two options.

First option (imho recommended):

Change your swap function to accept pointers instead of references.

void Swap(stub *s1, stub *s2) {

    stub temp = *s2;



    *s1 = *s2;

    *s2 = temp;

}

Second option:

Dereference the parameters before passing to swap:

Swap(*(stubList[i]), *(stubList[i + 1]));

You have to undestand that the datatype in your list is a pointer to stub, the function Swap wants a reference, which are different things in C++.

For a better understanding I recommend reading this: https://www.geeksforgeeks.org/pointers-vs-references-cpp/