C++ Program to Calculate Average, Percentage Marks

Here you will learn and get code on finding the average and percentage mark of a student based on the marks entered by user in C++. You will go through the following three programs over here:

Find Average & Percentage Marks in 5 Subjects
Allow user to define number of subjects and maximum mark along with marks obtained in each subject
Find Average & Percentage Marks using user-defined Function

How to Find Average Mark ?

To find average marks in n number of subjects, just add all the marks and divide it by n. For example, to find average mark with marks obtained in three subjects say 10, 20, 30, then it will be:

avg = (10+20+30)/3
    = 60/3
    = 20

How to Find Percentage Mark ?

To find percentage mark, use following formula:

perc = ((marks obtained)/(total marks))*100

For example, if marks of three subjects are 10, 11, 12 out of 25. That is, the maximum mark is 25. And out of 25, the student got 10, 11, 12 in 3 subjects. Therefore, his/her percentage mark can be calculated as:

perc = ((10+11+12)/(25*3))*100
     = (33/75)*100
     = (0.44)*100
     = 44

Therefore, the percentage mark will be 44 percentage. Now let's move on to the program.

Find Average & Percentage Marks of Student in C++

To calculate average and percentage marks (in 5 subjects) of a student in C++ programming, you have to ask from user to enter marks obtained in 5 subjects.

Now place the summation result of 5 subject's mark in a variable say sum and place sum/5 in a variable say avg (average of 5 subjects). Then place sum/500*100 in a variable say perc (percentage marks), then display the result on the screen as shown here in the following program.

#include<iostream>
using namespace std;
int main()
{
    int i, mark[5];
    float sum=0, avg, perc;
    cout<<"Enter Marks obtained in 5 Subjects: ";
    for(i=0; i<5; i++)
    {
        cin>>mark[i];
        sum = sum+mark[i];
    }
    avg = sum/5;
    perc = (sum/500)*100;
    cout<<"\nAverage Marks = "<<avg;
    cout<<"\nPercentage Marks = "<<perc<<"%";
    cout<<endl;
    return 0;
}

This program was build and run under Code::Blocks IDE. Here is its sample run:

Now supply marks obtained in 5 subjects say Physics, Chemistry, Math, English, CS. Each mark should be entered out of 100. After supplying marks say 78, 92, 83, 81, 89, press ENTER key to see the following output:

Allow User to Define Maximum Mark

This program is same as of previous one. But there are two extra features added to it. The first one is, user is allowed to enter the number of subject, that how many subject running for his/her course. And the second is, user is allowed to enter maximum mark. Rest of the things will be same:

#include<iostream>
using namespace std;
int main()
{
    int i, n;
    float tot, arr[10], sum=0, avg, perc;
    cout<<"Enter Number of Subjects: ";
    cin>>n;
    cout<<"\nEnter Total Marks: ";
    cin>>tot;
    cout<<"\nEnter Marks obtained in "<<n<<" Subjects: ";
    for(i=0; i<n; i++)
    {
        cin>>arr[i];
        sum = sum+arr[i];
    }
    tot = tot*n;
    avg = sum/n;
    perc = (sum/tot)*100;
    cout<<"\nAverage Marks = "<<avg;
    cout<<"\nPercentage Marks = "<<perc<<"%";
    cout<<endl;
    return 0;
}

Here is its sample run, with user input:

3 as Number of Subjects
25 as Total Marks
10, 11, 12 as Marks Obtained in 3 Subjects

Press ENTER key after supplying the inputs as given above, here is the output you will see:

Using user-defined Function

This is the last program that also find and prints average and percentage marks. The only difference is, this program finds average and percentage marks using function namely averageMark() and percMark(). To learn more about function in C++, you can refer to its separate tutorial.

#include<iostream>
using namespace std;
float averageMark(float [], int);
float percMark(float [], int);
int main()
{
    int i, n;
    float arr[10], avg, per;
    cout<<"Enter Number of Subjects: ";
    cin>>n;
    cout<<"\nEnter Marks obtained in "<<n<<" Subjects: ";
    for(i=0; i<n; i++)
        cin>>arr[i];
    avg = averageMark(arr, n);
    per = percMark(arr, n);
    cout<<"\nAverage Marks = "<<avg;
    cout<<"\nPercentage Marks = "<<per<<"%";
    cout<<endl;
    return 0;
}
float averageMark(float arr[], int n)
{
    int i;
    float sum=0;
    for(i=0; i<n; i++)
        sum = sum+arr[i];
    return (sum/n);
}
float percMark(float arr[], int n)
{
    float perc;
    perc = averageMark(arr, n);
    return perc;
}

Here is its sample run:

Now enter the number of subjects running in your institute for your course. For example, if you're studying a course that includes 6 subjects, then enter 6. Since, there are 6 subjects running to your course, therefore enter marks obtained in all the 6 subjects (out of 100 each) and press ENTER key to see the average and percentage marks as shown in the output given below: