Student Marks Manager

Learn student marks manager through an executable example, then connect the small demonstration to production code.

Represent students as structs, calculate totals and averages, then classify results by clear thresholds. Keep grading logic in a function so it can be tested independently of input or output code.

This program evaluates two students with fixed marks to demonstrate the processing workflow.

Follow this diagram before executing the example. Check where a value or decision changes what runs next.

Expansion: add a persistent JSON or SQL store, import/export, grading-policy configuration, validation and table-driven tests. Specify whether averages are weighted and how ties are handled.

This example is a complete program. Save it as main.go or paste it into the Go Playground.

Go code

package main

import "fmt"

type Student struct {
	Name  string
	Marks []int
}

func average(marks []int) float64 {
	if len(marks) == 0 {
		return 0
	}
	sum := 0
	for _, mark := range marks {
		sum += mark
	}
	return float64(sum) / float64(len(marks))
}
func grade(avg float64) string {
	if avg >= 75 {
		return "A"
	}
	if avg >= 50 {
		return "B"
	}
	return "C"
}
func main() {
	students := []Student{{"Asha", []int{80, 90, 70}}, {"Ravi", []int{55, 60, 50}}}
	for _, s := range students {
		avg := average(s.Marks)
		fmt.Printf("%s average %.1f grade %s\n", s.Name, avg, grade(avg))
	}
}

Output

Asha average 80.0 grade A
Ravi average 55.0 grade B

Asha has an average of 80 and grade A; Ravi averages 55 and receives grade B under these illustrative thresholds.

• Specify how missing marks, an empty mark list and invalid scores are handled.
• Grade thresholds are application requirements, not built-in Go rules.

Add subject names, validate that marks are from 0 to 100, and sort students by average.

Tip: Edit the example above, predict the output, and run the modified code to test your reasoning.

You have practiced Student Marks Manager in a small, self-contained program. The important habit is to predict what runs, inspect the actual output and distinguish the language rule from the particular example.

Before continuing, make sure you can explain the program to someone who has not seen it, including the line that changes its result.