Computing Average

[Student1904]

// Hello, I need some help computing averages after reading from a file. The parameters for my computeAvg function has an error.

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

struct person
{
    string name;
    int age;
    float gpa;
};

void copyData(string fName, person x[]);
void displayData(person x[]);
void displayTeens(person x[]);
void computeAvg(person x[], float& ageAvg, float& gpaAvg);
void displayAvg(float& ageAvg, float& gpaAvg);

int main()
{
    person a[5];

    cout << "This is the content of array a: " << endl;
    copyData("data.txt", a);

    displayData(a);

    cout << "This is the list of teenagers: " << endl;
    displayTeens(a);

    cout << "The average age is: ";
	displayAvg(ageAvg, gpaAvg);

    system("pause");
    return 0;
}

void copyData(string fName, person x[])
{
    fstream f;

    f.open("data.txt", ios::in);

    for(int i = 0; i < 5; i++)
    {
        f >> x[i].name >> x[i].age >> x[i].gpa;
    }

    f.close();

}

void displayData(person x[])
{
    for (int i = 0; i < 5; i++)
    {
        cout << x[i].name << " " << x[i].age << " " << x[i].gpa << endl;
    }
}

void displayTeens(person x[])
{
    for(int i = 0; i < 5; i++)
    {
        if((x[i].age > 12) && (x[i].age < 20))
        {
            cout << x[i].name << endl;
        }
    }
}

void computeAvg(person x[], float& ageAvg, float& gpaAvg)
{
    float ageTotal = 0;
    float gpaTotal = 0;

    for(int i = 0; i < 5; i++)
    {
        ageTotal += x[i].age;
        gpaTotal += x[i].gpa;
    }

    ageAvg = ageTotal / 5;
    gpaAvg = gpaTotal / 5;
}

void displayAvg(float& ageAvg, float& gpaAvg)

{
	cout << ageAvg;
	cout << gpaAvg;
}

[Ganado]

Please, before anything else, edit your post and put the text [code] and [/code] around your code so that it is formatted.
e.g.

#include <iostream>
int main()
{
    std::cout << "Proper formatting & indenting!\n";
}

Also note that you are only giving your person array a size of 5, but you are attempting to iterate over 6 people. That will go out of bounds of your array.

[Student1904]

Okay, thank you. I fixed the array size, but I still need help computing the averages.

[Ganado]

You'd get help much faster if you told us what the error actually was, so that we would know what to look for.

 In function 'int main()':
32:13: error: 'ageAvg' was not declared in this scope
32:21: error: 'gpaAvg' was not declared in this scope
 

You never declare ageAvg or gpaAvg as variables.

Need to do something like:

    cout << "The average age is: ";
    float ageAvg;
    float gpaAvg;
    computeAvg(a, ageAvg, gpaAvg); //edited, I previously had written something wrong here
    displayAvg(ageAvg, gpaAvg);

[tibrado]

Student1904. First you need to call the computeAvg function, which computes the average. Second your computeAvg takes 3 arguments (Array struct, float, float).

computeAvg(a, ageAvg, gpaAvg); 

You also need to create a local variable ageAvg and gpaAvg.

float ageAvg; 
float gpaAvg; 

Your int main should look like this:

int main()
{
    person a[5];
    float ageAvg; 
    float gpaAvg;

    cout << "This is the content of array a: " << endl;
    copyData("data.txt", a);

    displayData(a);

    cout << "This is the list of teenagers: " << endl;
    displayTeens(a);

    cout << "The average age is: ";
    computeAvg(a, ageAvg, gpaAvg);
    displayAvg(ageAvg, gpaAvg);

    system("pause");
    return 0;
}

- By the way, I believe that computeAvg and displayAvg are redundant. Due to ageAvg and gpaAvg being local variable which you can simply print.