Problem Solving: Compiling Student Result

Use the multi-dimensional arrays to create a program that compiles the student results.

We'll cover the following

Compiling the result of the students

Write a program that compiles the result of students and displays it.

Problem statement

The program should take the following as input:

  • Total number of students
  • Total number of courses (assuming that every student has the same number of courses)
  • Every student’s roll numbers, names, and obtained marks for each course

The program should:

  • Compile the result and display the result with the roll number followed by the name and total marks of each student
  • Display the class topper at the end

Sample program

        Semester Detailed Result
______________________________________
# of students: 5
# of courses: 5
---------------------------
Roll# Name   C1 C2 C3 C4 C5
---------------------------
1     Alice  90 75 80 60 91 
2     Bob    94 70 80 70 97 
3     Marie  80 87 90 97 98 
4     Imran  80 60 70 70 55 
5     Ali    85 86 87 90 98 

        Compiled Result!
______________________________________
Roll#   Name           Marks
----------------------------
1       Alice         396
2       Bob           411
3       Marie         452
4       Imran         335
5       Ali           446

The topper of the class is: Roll#3  Name: Marie Marks: 452

Try it yourself

Try to solve the above problem on your own. Write your code in the playground below

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#include <iostream>
using namespace std;
int main() {
  // your code goes here
  return 0;
}

Enter the input below

To test your playground code, you can copy the data given below.

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1       Alice   90      75      80      60      91
2       Bob     94      70      80      70      97
3       Marie   80      87      90      97      98
4       Imran   80      60      70      70      55
5       Ali     85      86      87      90      98

Click the "Show Solution" button below to see the complete solution of approach 1.

Approach 1

Implementation guideline

Let’s solve the problem step by step.

Instruction: You should write or verify what you have coded in the playground above as you go through each step.

Step 1: Memory usage

Let’s start by initializing variables and arrays. We need the following variables:

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const int noOfStudents = 5; // # of students records 
const int noOfCourses = 5; // # of courses
int rows = noOfStudents; // noOfStudents maps to a number of rows
int cols = noOfCourses; // noOfCourses maps to number of columns
int RollNos[noOfStudents]={}; // for storing each roll#
string Names[noOfStudents]; // for storing each name
float StudentMarks[noOfStudents][noOfCourses]; // the marks of every student in each course.

Instruction: Add this memory part to the playground above.

Step 2: Loading data from the console

We will iterate through noOfStudents times (for the user to enter all the records). The format is as follows: roll number followed by the name followed by noOfCourses marks in each course.

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// Displaying the end user directions for entering records.
cout << "\tEnter semester records of "<<noOfStudents<<" students\n"<<endl;
cout << "\tFormat:"<<"Roll#\tName\t";
for(int c=0; c<noOfCourses; c++)
    cout <<"C"<<c+1<<'\t';
cout <<"\n\n";
// Entering records
for(int r=0; r<noOfStudents; r++)
{
    cout <<"Record# "<<r+1<<".\t";
    cin>>RollNos[r];
    cin>>Names[r];
        
    for(int c=0; c<noOfCourses; c++)
    {
        cin >> StudentMarks[r][c];
    }
}

Step 3: Result compilation and printing

We want to calculate each student’s total marks and maintain the top student record.

  • To maintain the top student marks, we have the maxMarks, maxRollNo, and maxName variables.

  • To sum the marks of each course, we have a total variable.

  • Inside the loop, we will sum the marks of each student course, compare each student’s marks, and update the maxMarks, maxRollNo, and maxName based on current marks. if the current marks are maximum, then the previous marks update the student record.

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int maxMarks = -1; 
int maxRollNo;
string maxName;
float total = 0;
cout << "Compiled Result...!!!\n\n";
cout << "\t---------------------\n";
for(int r=0; r<noOfStudents; r++)
{
    cout << RollNos[r]<<"\t"<<Names[r]<<": \t";
    total = 0;  
      // This initialization is needed here otherwise the 2nd student marks 
      // and the first students marks will be accumulated in total.
    for(int c=0; c<noOfCourses; c++)
    {
        total = total + StudentMarks[r][c];
    }
    cout << total << endl;
        // Maintaining the maximum record
    if(total>maxMarks)
    {
        maxMarks = total;
        maxRollNo = RollNos[r];
        maxName = Names[r];
    }    
}
cout << "The topper of the class is : Roll#"<<maxRollNo<< "  Name: "<<maxName <<" Marks: "<<maxMarks<<endl;

We will see how the functional approach will make the step-by-step implementation much cleaner.

Approach 2: Using functional and loading data

This time, we have Result.txt file in which we have the following data:

5 5
1       Alice   90      75      80      60      91
2       Bob     94      70      80      70      97
3       Marie   80      87      90      97      98
4       Imran   80      60      70      70      55
5       Ali     85      86      87      90      98

Here 5 5 means there are five records each having five courses.

Try it yourself

Here’s the playground where you should write the code using the functional approach per the guidance below:

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main.cpp
Result.txt
#include <iostream>
#include <fstream>
using namespace std;
#define maxMarksCount 50
#define maxRecords 50
int main()
{
    // Code here!
    return 0;
}

During the functional implementation, we should remember that we will try to decouple the compilation and printing processes as much as possible. How can we do that?

Let’s look into the detailed implementation.

Implementation steps to follow

Here’s the main flow of the program.

Step 0: Memory requirement

Before looking at the hint, figure out the variables and arrays you will need to code in the functional implementation.

Step 1: Loading the records from the file

Look at the Result.txt file and figure out which variables we need in this step. Write a function recordLoader(), which should load the entire file along with all the parameters on which the entire program should be working.

Step 2: Printing the loaded data

This is usually a good practice for a developer and end user to display whatever data has been loaded into the program’s memory. The developer needs it because they should be sure the data is loaded properly and ready for processing, and the end user should also see it because it looks nice on the console.

Let’s make the function, printRecord(), which will print the record. Figure out what variables we need to pass so that we should be able to print the following:

        Semester Detailed Result
______________________________________
# of students: 5
# of courses : 5
---------------------------
Roll# Name   C1 C2 C3 C4 C5
---------------------------
1     Alice  90 75 80 60 91 
2     Bob    94 70 80 70 97 
3     Marie  80 87 90 97 98 
4     Imran  80 60 70 70 55 
5     Ali    85 86 87 90 98

Step 3: Compiling the result

This is the most important step involving computing the compiled total marks of each student as well as it should find out who is the student who got the maximum marks.

To accomplish this step, we’ll make a function compileResult(). Think before looking at the solution and what the arguments are on which this function should perform.

Step 4: Displaying the compiled result

After compiling the result, we need to display the final result with the student who obtained the maximum marks.

For this, let’s make the function that should display the following output:

        Compiled Result!
______________________________________
Roll#   Name           Marks
----------------------------
1       Alice         396
2       Bob           411
3       Marie         452
4       Imran         335
5       Ali           446

The topper of the class is: Roll#3  Name: Marie Marks: 452

Final step: complete the main function

Now that we’ve implemented all the functions, we should test each function one by one. The main() function should like the following:

Let’s look at the complete implementation:

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main.cpp
Result.txt
5 5
1       Alice   90      75      80      60      91
2       Bob     94      70      80      70      97
3       Marie   80      87      90      97      98
4       Imran   80      60      70      70      55
5       Ali     85      86      87      90      98

Exercise: Print maximum marks for the specified course

You must be wondering why we used arrays to read data from the file and then process and store it, whereas we could've also processed the data line by line and output the result without storing it. The reason is simple—we stored the results in an array, allowing us to write functions to query the data.

In this exercise, you'll have to implement a function, computeHighestMarksForCourse(), which takes the course index for which the highest score is to be returned. Utilize the playground below for your implementation. And if you get stuck, feel free to look at the solution.

5 5
1       Alice   90      75      80      60      91
2       Bob     94      70      80      70      97
3       Marie   80      87      90      97      98
4       Imran   80      60      70      70      55
5       Ali     85      86      87      90      98
Playground: Print maximum marks for specified course