arrays question

[abaz01]

aight so im trying to write a program that takes in one value of an array and quaruples it each time for 6 times, i cant get the rest of the numbers to quadruple besides the first, plz help. heres my code:

#include<iostream>

using namespace std;

int main()
{
const int num = 6;
float myArray[6];
float sum = 0;
float quad = 0;
cout << "Please enter a number " << endl;
cin >> myArray[0];

for (int x = 0; x<num; x++)
{
sum = 4*myArray[0];

cout << sum <<" \t";
}
return 0;
}

[shadow123]

If I understand you correctly, you want the user to input numbers for each array element. Yeah?
So you have to loop throw the items:

for(int i = 0; i < num; i++) {
    cout << "Please enter " << (i+1) << ". number: ";
    cin >> myArray[i];
}

Now you should see what's wrong with your calculation loop ;o)

[Moschops]

Firstly, your code only takes in one number. There are no "rest of the numbers". You only put a number into myArray[0], so myArray[1] to myArray[5] will have garbage values in.

That said, when your code gets round to multiplying the numbers, it always multiplies myArray[0].
sum = 4*myArray[0];

Did you mean this?
sum = 4*myArray[x];

Edit: NinJARed again. :(

[abaz01]

i will input one value and the program quadruples the last number for example if i input "1", the answer should be 4, 16, 64, 256, ...

[Moschops]

Then what exactly is that array for?

int x;
cin >> x;
for (int i=0;i<numberOfIterations; ++i)
{
  x = x*4;
  cout << x << " ";
}

[abaz01]

heres the question - "Define a float type array with 6 values using a constant value variable. The user should be prompted to fill the first value then the array should be populated by quadrupling the previous value in the array"

[Moschops]

You've been given enough example code above now to do that.

[abaz01]

@Moschops no i got it i was just responding to the question about what exactly the array was for...i appreciate your help.

[ThangDo]

#include<iostream>

using namespace std;

#define MAX_SIZE 	(6)

int main()
{
 	float myArray[MAX_SIZE];
 	float myNum;
 	
 	cout << "Enter first Number: ";
 	cin >> myNum;
 	
 	//assign the number to the first element of array
 	myArray[0] = myNum;
 	
 	//populate the array
 	for (int i = 0; i < MAX_SIZE; i++)
 	{
	 	myArray[i + 1] = 4 * myArray[i];
	 	
	 	cout << myArray[i] << endl;
	}
	
 	cin.get();
 	return 0;
}

The problem with your code is at
sum = 4*myArray[0];
where you are using only

myArray[0]

and storing it to sum without making any changes to it.

[abaz01]

thanks i got it now thanks for all y'all help.

[shadow123]

@ThangDo
Did you mean

	//populate the array
 	for (int i = 0; i < MAX_SIZE-1; i++)
 	{
	 	myArray[i + 1] = 4 * myArray[i];
	 	
	 	cout << myArray[i] << endl;
	}

?
Or do I miss something? o.O

[ThangDo]

@shadow123: ah yes, my mistake. otherwise its gonna give an out of bound error.