C++ Little Problem

[Dakot]

hello , i want to cin n numbers then to sort the positive numbers in one array, the negative numbers in another array , then to print positive array. So let me explain , i run the program , i enter the 9 , then enter 1 2 3 4 5 6 7 8 -1 , after this it couts me the Positive array , but at the end it prints me some numbers , i have no clue where they came from . I know that there is another way to do that , but i want only with arrays. Help me pls)

#include <cstdlib>
#include <iostream>
#include <conio.h> 
using namespace std;

int main() {
int nNumber;
cout<<"Enter a Number"<<endl;
cin>>nNumber;
int nPozitive[nNumber] , nNegative[nNumber] , nTotal[nNumber];
cout<<"Enter "<<" "<<nNumber <<" "<<"Numbers" <<endl;
for (int i = 0; i<nNumber; i++)
{
	cin>>nTotal[i];
	
}
for (int j = 0; j < nNumber; j++) {
	if (nTotal[j]>0) {
		nPozitive[j] = nTotal[j];
	}
	else
	{
		nNegative[j] = nTotal[j];
}
}
for (int k = 0 ; k<nNumber; k++) {

cout<<nPozitive[k]<<endl;

}


getch();
return 0;

}

[thines01]

In this example, you only put a few even numbers into the new array, but you're printing a TOTAL amount of numbers not just the even ones. When your nPozitive is delcared on the stack (and not initialized), it can have ANY values in it.

[james6754]

And what compiler are you using exactly. I have not long started learning C++, but I did not think variable length arrays were valid C++?

[Dakot]

yes , and that is the difficulty i meet . How to print just the "filled places" from the array? is there a way to do that? or what must i do to get the program working good?

p.s MingW GCC 4.6.1 32-bit

[thines01]

You also will need to call "new" on the array for the total.

[Dakot]

@thines01 , can you rewrite the code? so i can see where i made mistakes.. thanks.

[thines01]

I would start out like this:

#include <iostream>
#include <conio.h>
using namespace std;

int main()
{
	int nNumber = 0;
	cout<<"Enter an amount of numbers: ";
	cin>>nNumber;

	int* nTotal = new int(nNumber);
	int* nPositive = new int(nNumber);
	int* nNegative = new int(nNumber);

	cout<<"\nNow enter "<<nNumber <<" Numbers\n" <<endl;

	for (int i=0; i<nNumber; i++)
	{
		cout << "Enter number (" << (i+1) << "): ";
		cin>>nTotal[i];
	}

// code continues here...

Then make a counter to keep track of the positive numbers and one to keep track of the negative numbers.
THOSE will be the amounts you print of each (not the nNumber)

[Dakot]

finally i solved it) huh.

#include <cstdlib>
#include <iostream>
#include <conio.h>
#include <iomanip>
using namespace std;
     
int main() {

/*---------------------------------*/
int nNumber;
cout<<"Enter n Number ";
cin>>nNumber;
/*---------------------------------*/
int nTotal[nNumber],nPos = 0, nNeg = 0;
int nPosnum[nPos] , nNegnum[nNeg];
//Place to declare Variables
/*---------------------------------*/
cout<<"Enter "<<nNumber<<" numbers"<<endl;
for (int i = 0; i < nNumber ; i++) 
{
	cin>>nTotal[i];
	if (nTotal[i]>0) 
	{
	nPosnum[nPos++]= nTotal[i];
	}
	else if(nTotal[i]<0)
	{
	nNegnum[nNeg++] = nTotal[i];
	}
     
}
//Here i cout the total of positive and negative numbers, then put them in array
/*---------------------------------*/
cout<<setw(21)<<left<<"Positive Numbers"<<"Negative Numbers"<<endl;

for (int k = 0 ; k < nPos ; k++) 
{
	cout<<nPosnum[k]<<endl;
}
//Here i @cout@ the positive numbers
/*---------------------------------*/
for (int l = 0 ; l <nNeg; l++)
{
	cout<<setw(21)<<left<<""<<nNegnum[l]<<endl;
}
//Here the negatives
/*---------------------------------*/
getch();
return 0;
     
}