C++ Problem

hello
can someone help me please with this exercise.
i can't solve it.

Write an averaging program. The program must prompt the user to enter a positive integer that specifies the number of values n the user
wishes to average. The program must then ask the user to input these n
values. The program should then compute the average of the values inputted and output it to the user.

thanks in advance.

What are you having trouble with? Here's some pseudo-code to get you going (which is exactly what you stated).

Code:

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prompt user for n number of integers
read in integers
find average of integers
cout the average

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this is what i had so far, but i am totally confused.

Code:

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#include <iostream>
#include <string>
using namespace std;

int main(){
       
        int nV;
        cout << "Enter the number of values to average: "; cin >> nV;
        int v[nV];

        for (int cnt = 0; cnt != nV; cnt++){

                cout << "[" << cnt << "] = ";
                cin >> v[cnt];
                }

        int avrg = 0;

        while (nV != -1)
                avrg += v[nV-1];

        avrg /= nV;
        cout << " Average = " << avrg;
}

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So what are you confused about? The better you ask questions, the better the answers will be.

--
Mats

You're going through an infinite loop here since nV isn't actually being decreased. You're just saying "value of nV minus one" but you're not actually changing nV.

Code:

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while (nV != -1)
                avrg += v[nV-1];

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Quote:

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There's nothing saying you can't do what he did. I do that myself even, it's part of programming. In a console program it's not a big. In windows API I can see it becoming a problem in different areas, though.

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I guess my statement was vague, what I mean is that before you can use an array you have to declare the size first:

Code:

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int v[ 10 ];

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Quote:

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There's nothing saying you can't do what he did. I do that myself even, it's part of programming. In a console program it's not a big. In windows API I can see it becoming a problem in different areas, though.

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I guess my statement was vague, what I mean is that before you can use an array you have to declare the size first:

Code:

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int v[ 10 ];

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you don't of course have to retain all values in memory...
All you have to retain is the sum of the values already entered and the number of values entered.
The average can be simply computed as that sum divided by that number at any time.

You'd probably want to use an unsigned long for the sum instead of an unsigned int of course.

Code:

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        int nV;
        cout << "Enter the number of values to average: "; cin >> nV;
        int v[nV];

---

In C/C++ you should declare the size of the array first, you cannot just declare the size of the array in runtime

Code:

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        while (nV != -1)
                avrg += v[nV-1];

        avrg /= nV;

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As scwizzo stated, you're not actually decrementing the value of nV, so you will be having an infinite loop right there.

let's say you're decrementing nV, that's still a logical error. Since you are decrementing the value of nV and using it to divide the total of avrg to have the average of the values, you will be having a negative value.

it would be better if you could declare a variable that will traverse in the array for you to sum up all the values that you entered in the array.

Quote:

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Originally Posted by $l4xklynx

In C/C++ you should declare the size of the array first, you cannot just declare the size of the array in runtime

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There's nothing saying you can't do what he did. I do that myself even, it's part of programming. In a console program it's not a big. In windows API I can see it becoming a problem in different areas, though.

As for that loop, I would probably use a for loop to go through the array, but you can do it however you feel fit.

Quote:

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There's nothing saying you can't do what he did.

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Except for the current C++ standard, meaning that it is an extension, but really, who cares about standards?!

Soma

Fortunately you can avoid the whole "not defined" thing by doing this problem the easy way, without any arrays at all. (Why read and then process -- why not process while you read?)

Quote:

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Originally Posted by scwizzo

There's nothing saying you can't do what he did. I do that myself even, it's part of programming. In a console program it's not a big. In windows API I can see it becoming a problem in different areas, though.

As for that loop, I would probably use a for loop to go through the array, but you can do it however you feel fit.

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But C++ is no slouch. Even though it may not support C variable-sized arrays, it does support dynamic arrays:

Code:

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std::vector v(vX);

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Or even

Code:

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std::vector v;
int x;
for (int i = 0; i < vX; i++)
{
    cin >> x;
    v.push_back(x);
}

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Keep to the standard!