Calculating average using struct, vector, and for loop.

[theroc12]

Hi as the title says I need to use a struct, vector, and for loop to calculate the average mark.
The program runs but it does not calculate the average correctly.

#include <iostream>
#include <vector>
#include <cmath>
using namespace std;

struct Record{
	float mark;
};

vector<Record> a;
float ave(vector<Record> &a);

int main()
{
	Record b;
	int student;
	
cout << "how many students?: ";
cin >> student;

for(int i=0;i<student;i++)
{
cout << "enter mark - ";
cin >> b.mark;
a.push_back(b);
}

float ave(vector<Record> &a);

cout << ave;

}


float ave(vector<Record> &a){
	float sum;
	
	for(int i=0; i<a.size();i++)
	{
		sum += a[i].mark;
	}
	float avg = sum/a.size();
	return avg;
}

[MistahMoose]

Firstly, Use meaningful variable names, A lot of problems are solved by an easy to read code.
IE your variables make more sense like:
vector<Record> StudentScores
int NumberOfStudents
Record StudentGrades

I believe You've declared your struct wrong.
You declared a struct with only float in it, which is pointless to have a struct containing one variable.
Then followed creating a vector of that struct, which is the same as just creating a vector of floats. Since your struct only contains float.
Basically useless when you could just do a vector of whatever type you wanted rather. Unless the teacher wants a struct containing one variable.

You're also calling your function incorrectly.
You are redeclaring it rather than calling it in main

float ave(vector<Record> &a);
// should be
ave(a);
//This might be why you arent printing what you want to. I imagine its not returning anything significant. 

(also you cant cout ave since its not declared properly, it should be cout << (ave(a)) if you wanted to cout average in main.)

Followed by your function not initializing sum. How can you add to sum if you dont know its value?

I would begin by fixing these issues then taking a second look. Writing an algorithm before you begin will benefit you.

Sorry for all the edits, Just kept trying to give more help lol

[MistahMoose]

Attempt to fix your code before looking ;)
I did not use struct, But it is easily modifiable to include that.

#include <iostream>
#include <vector>
#include <cmath>
using namespace std;

int StudentAverage(vector<int> &StudentScores);

int main()
{
    
    int StudentGrade;
    vector<int> ListStudentScores;
    int NumberOfStudents;
	
    cout << "How many students in the class?: ";
    cin >> NumberOfStudents;

    for(int i = 0; i < NumberOfStudents; i++)
    {
        cout << "Enter Student # " << i + 1 << "'s Score: ";
        cin >> StudentGrade;
        ListStudentScores.push_back(StudentGrade);
    }

    cout << "Class Average Is: " << StudentAverage(ListStudentScores);

return 0;

}


int StudentAverage(vector<int> &ListStudentScores)
{
	int sum;
	sum = 0;
	for(int i=0; i<ListStudentScores.size();i++)
	{
		sum = sum + ListStudentScores[i];
	}
	int Average = sum/ListStudentScores.size();

	return Average;
}