Program to calculate Percentile of Students

Given an array containing marks of students, the task is to calculate the percentile of the students. The percentile is calculated according to the following rule: 

The percentile of a student is the % of the number of students having marks less than him/her.

Examples:

Input: arr[] = { 12, 60, 80, 71, 30 }
Output: { 0, 50, 100, 75, 25 }
Explanation:
Percentile of Student 1 = 0/4*100 = 0 (out of other 4 students no one has marks less than this student) 
Percentile of Student 2 = 2/4*100 = 50 (out of other 4 students, 2 have marks less than this student) 
Percentile of Student 3 = 4/4*100 = 100 (out of other 4 students, all 4 have marks less than this student) 
Percentile of Student 4 = 3/4*100 = 75 (out of other 4 students, 3 have marks less than this student) 
Percentile of Student 5 = 1/4*100 = 25 (out of other 4 students only 1 has marks less than this student) 

Approach:

• So basically, the percentile is a number where a certain percentage of scores fall below that number. 
  
• For example: If in an examination a student’s percentile is 75 then it means that the student has scored more than 75% of students who took the test. 
  
• Now, in order to calculate percentile we have the following formula:
  PERCENTILE = (NUMBER OF STUDENTS WHO SCORED BELOW OR EQUAL TO THE DESIRED STUDENT/ TOTAL NUMBER OF STUDENTS – 1) * 100
  

Below is the implementation of the above approach:

C++

// C++ program to calculate Percentile of Students

#include <bits/stdc++.h>
using namespace std;

// Function to calculate the percentile
void percentile(int arr[], int n)
{
    int i, j, count, percent;

    // Start of the loop that calculates percentile
    for (i = 0; i < n; i++) {

        count = 0;
        for (int j = 0; j < n; j++) {

            // Comparing the marks of student i
            // with all other students
            if (arr[i] > arr[j]) {
                count++;
            }
        }
        percent = (count * 100) / (n - 1);

        cout << "\nPercentile of Student "
             << i + 1 << " = " << percent;
    }
}

// Driver Code
int main()
{
    int StudentMarks[] = { 12, 60, 80, 71, 30 };
    int n = sizeof(StudentMarks) / sizeof(StudentMarks[0]);
    percentile(StudentMarks, n);

    return 0;
}

Java

// Java program to calculate Percentile of Students
class GFG
{

    // Function to calculate the percentile
    static void percentile(int arr[], int n)
    {
        int i, count, percent;

        // Start of the loop that calculates percentile
        for (i = 0; i < n; i++)
        {

            count = 0;
            for (int j = 0; j < n; j++)
            {

                // Comparing the marks of student i
                // with all other students
                if (arr[i] > arr[j])
                {
                    count++;
                }
            }
            percent = (count * 100) / (n - 1);

            System.out.print("\nPercentile of Student "
            + (i + 1) + " = " + percent);
        }
    }

    // Driver Code
    public static void main(String[] args)
    {
        int[] StudentMarks = { 12, 60, 80, 71, 30 };
        int n = StudentMarks.length;
        percentile(StudentMarks, n);
    }
}

// This code is contributed by Rajput-Ji

Python

# Python3 program to calculate Percentile of Students

# Function to calculate the percentile
def percentile(arr, n):
    i, j = 0, 0
    count, percent = 0, 0

    # Start of the loop that calculates percentile
    while i < n:

        count = 0
        j = 0
        while j < n:

            # Comparing the marks of student i
            # with all other students
            if (arr[i] > arr[j]):
                count += 1
            j += 1
        percent = (count * 100) // (n - 1)

        print("Percentile of Student ", i + 1," = ", percent)
        i += 1

# Driver Code

StudentMarks = [12, 60, 80, 71, 30]
n = len(StudentMarks)
percentile(StudentMarks, n)

# This code is contributed by mohit kumar 29

C#

// C# program to calculate Percentile of Students
using System;

class GFG
{

    // Function to calculate the percentile
    static void percentile(int []arr, int n)
    {
        int i, count, percent;

        // Start of the loop that calculates percentile
        for (i = 0; i < n; i++)
        {
            count = 0;
            for (int j = 0; j < n; j++)
            {

                // Comparing the marks of student i
                // with all other students
                if (arr[i] > arr[j])
                {
                    count++;
                }
            }
            percent = (count * 100) / (n - 1);

            Console.Write("\nPercentile of Student "
            + (i + 1) + " = " + percent);
        }
    }

    // Driver Code
    public static void Main()
    {
        int[] StudentMarks = {12, 60, 80, 71, 30};
        int n = StudentMarks.Length;
        percentile(StudentMarks, n);
    }
}

// This code is contributed by AnkitRai01

Javascript

<script>

// Javascript program to calculate
// Percentile of Students

// Function to calculate the percentile
function percentile(arr, n)
{
    var i, count, percent;

    // Start of the loop that calculates percentile
    for (i = 0; i < n; i++)
    {

        count = 0;
        for (var j = 0; j < n; j++)
        {

            // Comparing the marks of student i
            // with all other students
            if (arr[i] > arr[j])
            {
                count++;
            }
        }
        percent = (count * 100) / (n - 1);

        document.write("\nPercentile of Student "
        + (i + 1) + " = " + percent + "<br>");
    }
}

// Driver Code
var StudentMarks = [ 12, 60, 80, 71, 30 ];
var n = StudentMarks.length;

percentile(StudentMarks, n);

// This code is contributed by Khushboogoyal499

</script>

Output:

Percentile of Student 1 = 0
Percentile of Student 2 = 50
Percentile of Student 3 = 100
Percentile of Student 4 = 75
Percentile of Student 5 = 25

Time Complexity: O(n²)

Auxiliary Space: O(1)