C++ Problem

[Tazzy]

Hello people I have only a little problem with this task.

I think I have solved the rask right but I am not sure perhaps all experts here can help me:

Task:

It is a function to be created, which by an array a with the method "Sort
Mix "ascending.
Function using recursion: sortMerge (n, a)
Here the procedure is as follows:
If an item contains a maximum of one is finished (already sorted)
otherwise
Create 2 matching arrays b and c
Train 2 halves of the array and save it in a new array b and c
Note:
a new array of names h and m elements can be generated as follows:
double * h = new double [m];
The type is double; other similar types;
m is an expression / a variable of type int
With delete [] h, you can delete it again.
Sort b and c with SortMerge
Mix b and c with the function of internship 9 and store the result in a
Delete b and c.

Proceed to creating a suitable program to test the function.
Example of a step in the algorithm:
Sort is a: 11 2 9 7 8 3 2 with 7 elements.
In 2 parts disassemble and store in b and c: b: 11 2 9 c: 7 8 3 2
The 2 parts with SortMerge by: b: 2 9 11 c: 2 3 7 8
The 2 parts to a mix a: 2 2 3 7 8 9 11


My programm:

#include <iostream>

using namespace std;


    void sortMerge(int n, int *a){
    void merge(int *a,int p,int *b,int q, int *c,int n);
    if (n>1) {

        int *b = new int[n/2];
        int *c = new int[(n + 1)/2];
        int i;
        for(i=0; i < n/2; i++) {
            b[i] = a[i];
        }
        for(i=n/2; i < n; i++) {
            c[i - n/2] = a[i];
        }

       
        sortMerge(n/2, b);
        sortMerge(n-n/2, c);

        
        merge(b,n/2,c,n-n/2,a,n);

       
        delete b;
        delete c;
    }
}


void merge(int *b,int p,int *c,int q, int *a,int n)
{
    int i=0,j=0,k=0;
    while(i<p && j<q)
    {
        if(b[i]<=c[j]) {
            a[k]=b[i];
            i++;
        } else {
            a[k]=c[j];
            j++;
        }
        k++;
    }
    if(i==p) {
        while(j<q) {
            a[k]=c[j];
            j++;
            k++;
        }
    } else {
        while(i<p) {
            a[k]=b[i];
            i++;
            k++;
        }
    }
}

When I try to run the programm , it shows an error.

undefined reference to winmain.

Can somebody please tell me what I am doing wrong and perhaps help me.

[Tazzy]

Hello all experts around. Can somebody tell me why my programm is not working?

Iam confused at the moment.

[Cubbi]

At the very least, you need to
1. replace

        delete b;
        delete c;

with

        delete[] b;
        delete[] c;

2. add a main function, for example

int main()
{
    int a[] = {11, 2, 9, 7, 8, 3, 2};
    sortMerge(7, a);
}

3. Set up your project to build a console application, so that it stops looking for winmain

[EssGeEich]

You have no entrypoint. Where should your program start from if you have no main/winmain ?

[Tazzy]

My Programm is now looking so :

#include <iostream>

using namespace std;

    int main(){
    void sortMerge(int n, int *a){
    void merge(int *a,int p,int *b,int q, int *c,int n);
    if (n>1) {

        int *b = new int[n/2];
        int *c = new int[(n + 1)/2];
        int i;
        for(i=0; i < n/2; i++) {
            b[i] = a[i];
        }
        for(i=n/2; i < n; i++) {
            c[i - n/2] = a[i];
        }

        // Arrays einzeln rekursiv sortieren
        sortMerge(n/2, b);
        sortMerge(n-n/2, c);

        // Arrays b und c zusammenfügen
        merge(b,n/2,c,n-n/2,a,n);

        // Arrays b und c wieder löschen
        delete [] b;
        delete [] c;
    }
}


void merge(int *b,int p,int *c,int q, int *a,int n)
{
    int i=0,j=0,k=0;
    while(i<p && j<q)
    {
        if(b[i]<=c[j]) {
            a[k]=b[i];
            i++;
        } else {
            a[k]=c[j];
            j++;
        }
        k++;
    }
    if(i==p) {
        while(j<q) {
            a[k]=c[j];
            j++;
            k++;
        }
    } else {
        while(i<p) {
            a[k]=b[i];
            i++;
            k++;
        }
    }
}

    }

Why is the programm still not working?

I don`t understand this.

Please help me.

[modoran]

You cannot declare functions inside other functions, like you do in line 6 and 7.

Put these before main().

void sortMerge(int n, int *a){
    void merge(int *a,int p,int *b,int q, int *c,int n);

Also your sortMerge() implementation is missing, you will get linker errors.

[Tazzy]

Hello I corrected my programm a little:

#include <iostream>

using namespace std;

    void sortMerge(int n, int *a){
    void merge(int *a,int p,int *b,int q, int *c,int n);
    int main(){

    if (n>1) {

        int *b = new int[n/2];
        int *c = new int[(n + 1)/2];
        int i;
        for(i=0; i < n/2; i++) {
            b[i] = a[i];
        }
        for(i=n/2; i < n; i++) {
            c[i - n/2] = a[i];
        }

        // Arrays einzeln rekursiv sortieren
        sortMerge(n/2, b);
        sortMerge(n-n/2, c);

        // Arrays b und c zusammenfügen
        merge(b,n/2,c,n-n/2,a,n);

        // Arrays b und c wieder löschen
        delete[] b;
        delete[] c;
    }
}


void merge(int *b,int p,int *c,int q, int *a,int n)
{
    int i=0,j=0,k=0;
    while(i<p && j<q)
    {
        if(b[i]<=c[j]) {
            a[k]=b[i];
            i++;
        } else {
            a[k]=c[j];
            j++;
        }
        k++;
    }
    if(i==p) {
        while(j<q) {
            a[k]=c[j];
            j++;
            k++;
        }
    } else {
        while(i<p) {
            a[k]=b[i];
            i++;
            k++;
        }
    }
}

}

But I really don´t understand what I should do now?

Also your sortMerge() implementation is missing, you will get linker errors.

Can somebody tell me how my implementation should be?

[EssGeEich]

You're going too fast.
You don't know what int main() is and you're already writing functions.
Try with a simpler example next time, begin here: http://www.cplusplus.com/doc/tutorial/

[Tazzy]

Yeah haha.I also think so but can you Tell me what is wrong in my Code please because I am Görings Mad with this task.

[Tazzy]

Can somebody tell what I should I correct in my programm?

Because my programm is still not working.

[vlad from moscow]

Why are you asking what is wrong and do not read compiler error messages?!!! It is the compiler that says what is wrong with your program.

[Tazzy]

My Compiler is telling that there is a Problem with One bracket. But i dont find the mistakes. Thats why I am asking.

[Tazzy]

Can only somebody Tell me how I can correct this Problem?

[Imadatobanisa]

Just please post all compling errors and linking errors here.
Maybe we can help you.

[Tazzy]

I am getting the error } before token.

Where is my mistake?

[FredFlintstone]

In previous program, compiler tells that in line "if (n>1)", "n" is undeclared.

Assign any value to array a, and assign the size of array "a" to n:

using namespace std;

int a[] = {11, 2, 9, 7, 8, 3, 2};
int n = 7;

void sortMerge(int n, int *a); // (deleted {)
void merge(int *a,int p,int *b,int q, int *c,int n);

int main(){


erase last }

Now builder tells: you are missing to define mergesort().

yet to resolve the recursion ...

I modified your program like this:
#include <iostream>
using namespace std;
int a[] = {11, 2, 9, 7, 8, 3, 2};
int n = 7;
void merge(int *a,int p,int *b,int q, int *c,int n);
void sortMerge(int n, int *a) {
if (n>1) {
int *b = new int[n/2];
int *c = new int[(n + 1)/2];
int i;
for(i=0; i < n/2; i++) {
b[i] = a[i];
}
for(i=n/2; i < n; i++) {
c[i - n/2] = a[i];
}
// Arrays einzeln rekursiv sortieren
sortMerge(n/2, b);
sortMerge(n-n/2, c);
// Arrays b und c zusammenfügen
merge(b,n/2,c,n-n/2,a,n);
// Arrays b und c wieder löschen
delete[] b;
delete[] c;
}
}
void merge(int *b,int p,int *c,int q, int *a,int n) {
int i=0,j=0,k=0;
while(i<p && j<q) {
if(b[i]<=c[j]) {
a[k]=b[i];
i++;
} else {
a[k]=c[j];
j++;
}
k++;
}
if(i==p) {
while(j<q) {
a[k]=c[j];
j++;
k++;
}
} else {
while(i<p) {
a[k]=b[i];
i++;
k++;
}
}
}
int main(){
sortMerge(7, a);
for (int i=0; i<n; i++) cout << a[i] << " ";
system("PAUSE");
return 0;
}

[Tazzy]

post erased

[Tazzy]

erased

[Tazzy]

erased

[Tazzy]

Sorry People your Forum postet my Comment 3 Times.